Listening Under the Line: Where It Happened, Episode 5
On 10 February 1962, the American pilot Francis Gary Powers and the Soviet agent Rudolf Abel passed each other on the white line in the middle of the Glienicke Bridge, the first of three spy exchanges there. I tell the story from the tunnel that the Americans and British dug from Rudow to tap Soviet military telephone lines, and why the KGB already knew about it. The tunnel was found in April 1956, and the bridge saw two more exchanges in 1985 and 1986.
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In this episode
0:00 Digging the tunnel
6:44 George Blake and the discovery
10:55 Where to see the tunnel
14:09 The bridge and the 1962 swap
16:57 Later swaps and today
Where to stand today
Glienicker Brücke, between Wannsee and Potsdam. Take bus 316 from S Wannsee to the last stop, Glienicker Brücke. The bus crosses the whole span first. Walk back to the metal band across the footpath at mid-span, read the words on it, and stand beside it where the white line once marked the border.
Schönefelder Chaussee, Altglienicke. The tunnel ran from Rudow as far as this road. For an original piece you can see, go to the water tower museum on Schirnerstraße.
Water tower museum, Schirnerstraße, Altglienicke. One original piece of the tunnel is on show here. Check its opening days on the district's page before you go.
Allied Museum, Clayallee 135, Dahlem. The museum owns a restored tunnel segment. During the Outpost Theater renovation, the permanent exhibition is condensed into the Nicholson Memorial Library. Check the museum’s current visitor information before going and ask which tunnel objects are accessible.
Read the full guide
The episode tells the story. My written guide covers the same subject in more detail: Cold War Berlin in 5 Key Locations You Can Still Visit.
Transcript (text)
Digging the tunnel
On the morning of 10 February 1962, two men reached the middle of a bridge in Berlin at the same moment. The Deutsches Spionagemuseum records the time as 8:52. One was Francis Gary Powers, the American pilot whose U-2 spy plane the Soviets had shot down. The other was Rudolf Abel, a Soviet agent held in the United States. Both crossed a white line across the middle of the bridge. One went into the West. The other went into the East. Hold that moment in mind. The story of how the two men came to be traded there starts underground, in the American sector, with a fear that two governments shared.
Today two metal bands mark the old border, one on each footpath at mid-span, and you can stand on them. You will hear when they were set in place at the end of this story. But the bridge is only the last act. The exchange was possible because of a tunnel that Western intelligence services built in secret, years before the bridge saw its first swap. From 1945 to 1990, Berlin was split into four sectors run by the wartime Allies, and the tunnel ran from the American sector into the Soviet one without anyone on the surface seeing the work. Picture a city where each side was listening to the other, and where neither side could say so out loud. To understand why the swaps happened on a bridge at all, you have to start with the fear that sent the Americans and the British digging.
The Americans and the British wanted early warning of a Soviet nuclear first strike. The Bundesarchiv, the German federal archive, gives this as the motive: a chance to hear the other side before it moved. It dates the decision to December 1953. The CIA and Britain's Secret Intelligence Service, known as SIS or MI6, ran the project together. The Americans called it Operation Gold, and the British called it Stopwatch. The CIA's own history says Allen Dulles, its director, approved the tunneling in January 1954. The British built the tunnel, and the Americans paid for it, the Bundesarchiv says.
The Bundesarchiv says a similar operation had already been run in Vienna, using several small tunnels. Berlin's version was one long tunnel. The digging began in Rudow, in the American sector of West Berlin. The CIA says the construction was covered by a United States Air Force radar site and a warehouse. The Bundesarchiv reproduces a photograph of a sign that refers to the American sector. From above ground, the cover was all anyone could see. Below it, a tunnel ran about 450 meters, which is 1,476 feet, toward the Soviet sector. The CIA gives the length as 1,476 feet, and the Allied Museum gives about 450 meters. It is one of the few numbers in this story that the sources agree on, so hold on to it as you picture the ground.
The Allied Museum says the tunnel ran from Neukölln and Rudow in the American sector to Treptow and Altglienicke in the Soviet sector. The target was the telephone lines linking the Soviet military headquarters with Moscow. The Berlin district's own page on Altglienicke says the cables ran under Altglienicke, and that the tunnel was driven as far as the Schönefelder Chaussee. The dates of the digging differ. The Bundesarchiv puts the start in the autumn of 1954. The CIA's legacy history says work began in February 1954 and took about a year. It also says the route was judged hidden from visual surveillance, so nobody watching from the street could see the work.
In May 1955 the tunnel and its listening station were finished. British technicians tapped the Soviet cables, the lines that carried the military's own calls. The Bundesarchiv says they did it without being noticed. The CIA gives 11 May 1955 as the start of collection. The recording ran for eleven months, which the Allied Museum gives as the life of the tunnel before its discovery. For that year, the listeners heard what the Soviet military said on its own telephone lines, and the recordings went onto magnetic tape, reel after reel.
The sources agree on one number: 50,000 reels of tape, according to the CIA and the Bundesarchiv. They do not agree on what that came to in conversations. The CIA counts 443,000 fully transcribed conversations and 1,750 intelligence reports, and it gives 40,000 hours of telephone conversations. The Allied Museum gives some 440,000 telephone calls, and the Bundesarchiv counts 380,000 recordings. Some of the material was political, including talk about the 20th Party Congress of the Soviet Union, held in February 1956. Each figure comes from one source's count, so treat them as estimates rather than a final tally.
Eleven months of tape, and the people who had planned it did not know their secret was already known. The Allied Museum calls the discovery spectacular, after eleven months of tapping. Its special exhibition ran from 27 April to 31 December 2006, and visitors could see, and even enter, sections of the original tunnel, the museum says. That story had ended in April 1956. But somebody on the other side already knew about the plan while it was still being prepared. Who was that, and how long had Moscow known?
George Blake and the discovery
The answer is George Blake, a British intelligence officer who was also a Soviet spy. The CIA's account says he told the KGB about the operation while it was still being planned. The Allied Museum says the betrayal came before the operation even began, which made it particularly explosive. Both sources agree on the core fact: by the time the tunnel was built, the KGB already knew it was coming. The people who dug it did not know that. They believed they were building a secret in the ground, and Moscow already had the plan.
The CIA's legacy history says the KGB had been aware of the project from its start, and that it let the operation run until April 1956 to protect Blake. The Bundesarchiv reads it in a similar way. In its account, the Soviets did not interfere, because they wanted to protect one of their most important agents in the Cold War. The article gives that as its own reading, not as a documented order. For almost a year, the listeners believed their secret was safe, while Moscow kept quiet and let the tapes run.
The discovery came in April 1956, and the Soviet side made it public. The Allied Museum says units of the Soviet army stationed in East Germany found the tunnel that month, after it had run for some time. The Bundesarchiv dates the dig to 22 April, when Soviet and East German crews broke open the Schönefelder Chaussee in Altglienicke, where the tunnel ended. The Group of Soviet Forces in Germany ordered the work, and the Kasernierte Volkspolizei, an East German police force, carried it out. The CIA gives 22 April as the Berlin date and 21 April as the US date. It places the digging at a muddy municipal cemetery in Altglienicke, so the sources disagree on where the ground was opened.
The official explanation was a repair job on faulty underground cables. The CIA's story says the Soviets accidentally discovered the tunnel while supposedly repairing those cables. The Bundesarchiv adds two details. On 23 April, the Soviet military commandant, Kozjuba, announced the discovery at an international press conference. On 25 April, Erich Mielke, then first deputy minister for state security, sent a photo album of the tunnel to Walter Ulbricht, the East German leader. The Bundesarchiv credits its photographs to the Stasi records archive.
The archive also notes that East German propaganda called the builders American gangsters. In an East German exhibition from 1957 to 1961, the Bundesarchiv says, a genuine piece of the tunnel was shown. It reads the staged discovery as a show of strength by Khrushchev. Those are readings, not facts, and they show how the day was used. The tunnel's first public story was written in East Berlin, and it was not the story the listeners in the West had planned. Blake was in Berlin in 1956, on a new assignment, the same archive says. Britain arrested him after his exposure, and he later fled to socialist states.
In 1980 Blake spoke at a panel event at the Edgar André school, an East German intelligence school, according to the Bundesarchiv. He praised the Soviet cover story: the Soviets had made a false technical explanation for the discovery believable, and so protected his identity. You can still see one original piece of the tunnel in Altglienicke, in the water tower on Schirnerstraße. The Berlin district's page says the museum there opens on the last Sunday of each month, from 14:00 to 17:00. Check that before you go, because opening times change.
Where to see the tunnel
Then walk out to the Schönefelder Chaussee, the road in Altglienicke where the crews dug in 1956. The sources behind this episode name no plaque there, so the road itself is the place to stand. Look at the stretch where the crews dug, and picture the cables under it, carrying the Soviet military's calls. The crews officially said they were repairing a line, and the Bundesarchiv says they worked for the Soviet forces. That line had been tapped for almost a year. The tunnel that tapped it began in West Berlin, about 450 meters away. Stand there long enough and you will see how close the two sides were.
The other place is in Dahlem, at Clayallee 135. The Allied Museum occupies the former Outpost cinema, a building that is a designated historic landmark. From 1945 to 1994 the American army ran its Berlin headquarters from a complex on this road, and the road is named after General Lucius D. Clay. The American flag came down there for the last time on 15 September 1994, according to the Berlin heritage office. After the division of Germany ended, the barracks grounds were cleared by the US forces. Picture that flag coming down. Truman Plaza, the garrison's shopping center, lay past the headquarters on Clayallee. The museum's listing gives opening hours of Tuesday to Sunday, 10:00 to 18:00.
The Allied Museum says it has owned a restored segment of the tunnel since 1997, and that the segment is on display in its permanent exhibition. Berlin's museum portal describes the museum as documenting the Western powers' role in Berlin from 1945 to 1994. The building is the next thing to check. The portal says the Outpost Theatre is closed for urgent maintenance until further notice, and that its highlight objects are shown in the Nicholson library, where the portal also lists the Berlin spy tunnel among the museum's highlights.
So ask at the desk which room holds the tunnel piece this year. Take your time in that room, because the tunnel is one of the few objects in this story you can actually stand beside. A tunnel can tell you what the other side is saying, but it cannot bring a person back across a line. For that, the two sides needed a place where they could stand face to face, with the border between them. A bridge already stood in the right place, and it is the one that brings you back to the morning of 10 February 1962. What would the two sides actually hand over, and how could either of them know the other would keep its word?
The bridge and the 1962 swap
Back to the bridge. It stood there long before the Cold War, and it still stands today. The Glienicke Bridge is a steel bridge, built in 1906 and 1907. It runs between Wannsee, in West Berlin, and Potsdam, in the GDR. After the war it was rebuilt between 1947 and 1949, and the Berlin heritage office says it was then called the Brücke der Einheit, the Unity Bridge. Be careful with the sides, because they are easy to reverse. The east end of the bridge was West Berlin, on the Wannsee side. The west end was Potsdam, in the GDR. The border ran through the exact middle of the span.
From May 1952, only vehicles of the Allied military missions could cross the bridge, according to the Bundesarchiv. After the Wall went up on 13 August 1961, the Czechoslovak, Polish and Yugoslav military missions in West Berlin could cross as well, and so could other diplomats. On the Potsdam approach you can still see monumental colonnades, which line the road on both sides. For nearly a decade, the bridge was reserved for official vehicles. A 1985 letter in the Bundesarchiv file asks for a decision to open a border crossing point at the bridge. The archive page does not say whether it opened.
Powers had flown a U-2 high over the Soviet Union, and the Soviets shot the plane down over their own territory. Abel was the Soviet agent in American hands. Each side wanted its own man back, and the exchange was set for the bridge. The Spionagemuseum says the two men crossed the white line at mid-bridge at 8:52 a.m., at the same moment, and passed each other without a greeting. The New York Times reported the same time, 8:52 a.m. in Berlin. Before the swap, each side checked identity with a witness, an old comrade for Abel and a former schoolmate for Powers.
The public learned of the exchange only after both men were on their way, the museum says. The museum also places the American student Frederic Pryor first. Pryor, arrested in 1961 on charges of aiding an escape and of espionage, was freed at Checkpoint Charlie before the bridge swap began. The New York Times, reporting the swap, said Pryor was released at the Friedrichstrasse checkpoint just before the two men were exchanged. The lawyer Wolfgang Vogel acted as intermediary, and he appears again in the later exchanges.
Later swaps and today
Twenty-three years after the first swap, on 11 June 1985, the bridge carried a much bigger exchange. The Bundeszentrale für politische Bildung says 23 people held in the East went to the West, in return for four Eastern bloc spies. The four were Marian Zacharski of Poland, Penyu Kostadinov of Bulgaria, and two East Germans, Alfred Zehe and Alice Michelson. The Spionagemuseum says the exchange began around midday and took about an hour, with the Western agents arriving by bus from Potsdam. Counts differ by source. The museum gives 25 Western agents, and a 1985 news report describes 25 freed, 23 of whom crossed to the West.
The last exchange came on 11 February 1986. The dissident Anatoly Shcharansky crossed first, and he crossed alone. The Spionagemuseum says that showed the Americans did not regard him as an agent. It also says he was given trousers that were too big and had no belt. The museum names the Kocher couple among those exchanged, described as KGB agents who lived in the United States and spied on the CIA. A telegram from the US embassy in Bonn, dated 11 February 1986, describes how Shcharansky 'crossed the Glienicker Bridge in West Berlin into the free world.' Three exchanges took place on this bridge in all, in 1962, 1985 and 1986.
The bridge was open to everyone again from 10 November 1989, the Berlin heritage office says. Potsdam's city website says it reopened right after the Wall fell. On 13 August 2012, two steel bands were unveiled and set into the footpaths, one on each side, at mid-span. Each is 1.90 meters long and carries the words Deutsche Teilung bis 1989, German division until 1989. A white line had marked the border during the Cold War. The artist Bob Bahra designed the bands, each eight centimeters wide, and they now mark the old border line permanently.
Steven Spielberg's 2015 film, Bridge of Spies, tells the story of the 1962 swap, and it follows the lawyer James Donovan, who negotiates it. Berlin's city website says the bridge became known by the same name because of the Cold War exchanges. The Berlin heritage office files the bridge under the UNESCO World Heritage site Palaces and Parks of Potsdam and Berlin. Before you go, check the footpaths, because roadworks on the bridge can close them. If one is blocked, come back another day and keep to the footpath when you do come, not the lane.
So the tunnel and the bridge are one story. A tunnel from Rudow heard the Soviet side talk for about eleven months, and a bridge between Wannsee and Potsdam later gave back the people each side had caught. Both were built on the same fact: the city was divided, and each side wanted what the other held. Today the tunnel can be seen in two places you can stand next to. One is an original piece in the water tower museum in Altglienicke. The other is a restored segment that the Allied Museum says is on display in Dahlem, if the exhibition is open when you go. The digging began in Rudow, and the sources here point to no monument there, so go for the street and the picture. If you have only one afternoon, start at the bridge, and check the museum's opening status before you go to Dahlem.
The last place to stand is the bridge itself. Take bus 316 from S Wannsee to its last stop, Glienicker Brücke, on the Potsdam end of the bridge. The bus crosses the whole span before it stops. Walk back toward mid-span until you reach the metal band across the footpath. Read the words on it first: Deutsche Teilung bis 1989. Then stand beside it and look along the bridge in both directions. The footpaths run on both sides, so you can walk the whole span. The answer to the question at the end of the last chapter is simple: people, one at a time.
Sources
The podcast is narrated with an AI voice; the short breaks are read in my own voice.
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Image credits
Source and licence details for the photograph used on this page.
Cover: Glienicke Bridge at night, photo by Matthias Süßen, CC BY-SA 4.0, via Wikimedia Commons. Cropped to 3:2 and resized; no other changes.