Digging began in September 1954. To camouflage operations at the tunnel mouth, and to provide space for all the necessary equipment, a warehouse disguised as a radar installation was constructed. As the tunneling progressed, dirt and debris were brought up to the warehouse and packed in cartons prominently labeled “radar equipment.” Despite having to pump out ground water as they dug, U.S. Army engineers made good time, finishing the tunnel by the end of February 1955. A month later British electronics experts completed a “tap room” filled with the latest eavesdropping equipment. Anglo-American experts immediately began listening in to everything the Russians passed down their cable. It appeared to be the greatest espionage triumph since the “Ultra” decoding of Nazi naval signals in World War II.
There was only one problem: the Soviets knew all about it. A KGB “mole” in MI6, George Blake, had informed his Russian controllers about the enterprise as soon as it began. This of course enabled the Soviets to precensor the conversations they passed along the tapped cable. Had they wanted to, they could have fed the eavesdroppers nothing but misinformation, but this might have aroused suspicion and compromised Blake. Therefore the Russians tossed the Anglo-Americans a few pieces of useful data from time to time. After about a year, however, they decided to put an end to this unique party line. The trick was to uncover the operation “accidentally,” so as not to endanger their mole. A series of heavy rainstorms in spring 1956, which caused some electrical shorts, gave them the pretext they needed to dig up the cable and “discover” the tunnel.
Markus Wolf was with the Soviet team that broke into the tunnel on April 22, 1956. He was amazed by the sophisticated equipment in the “tap” room, which was more advanced than anything the KGB or the Stasi had. Contrary to some contemporary reports, the Soviets did not actually catch any Western technicians red-eared. The eavesdroppers had gotten just enough advance warning of the break-in to scurry out of the tunnel (and, as a little joke, to put up a hand-lettered sign at their end, saying, “You are now entering the American sector”). Wolf found the sign amusing but he was not amused by the fact that the Soviets had told the Stasi nothing about the tunnel operation until the moment they decided to uncover it. As he complained in his memoirs, the Russians had “protected their own conversations, [but] they never told us anything, leaving us unguarded and exposed.”
Moscow expected to score a propaganda coup by exposing the Berlin Tunnel, but it did not turn out that way. Rather than writing about how devious the Anglo-Americans were, most reporters invited to inspect the tunnel praised the West’s resourcefulness and ingenuity. The Soviets therefore decided that the less said about this matter, the better. On the other hand, they could hardly put the tunnel out of their minds, for it pointed up their own vulnerability in Berlin. West Berlin might be an isolated Western outpost, but its very existence deep inside the Soviet imperium made it a threat to Russian security—not to mention a pressing challenge to the very integrity of Moscow’s East German client.
The Most Dangerous Place in the World
In the late 1950s the Soviets decided to try once again to force the West out of Berlin. On November 10, 1958, Khrushchev told a Soviet-Polish Friendship Rally in Moscow that the “time has clearly come for the Powers which signed the Potsdam Agreement to renounce the remnants of the regime of occupation in Berlin and thus make it possible to create a normal situation in the capital of the GDR.” A “normal situation” in Soviet eyes meant control over the entire city by the “sovereign state” of the GDR. Two weeks later, Khrushchev sent notes to Washington, London, and Paris proposing that the “natural solution” in Berlin would be to reunite the city and make it “part of the State on whose land it is situated.” But since the Western powers were unlikely to embrace this plan, Khrushchev said he would be willing to discuss turning West Berlin into a “free city” under United Nations protection. If the West was unprepared to accept even this alternative, Moscow would have no choice but to sign a separate peace treaty with East Germany, thereby eliminating the legal justification for the continued Allied occupation of Berlin. The West was given six months to deal satisfactorily with the Soviets, or face being forced out of Berlin by East Germany. Moscow’s note also warned against any “reckless threats of force” by the Western powers: “Only madmen can go to the length of unleashing another World War over the preservation of privileges of occupiers in West Berlin.”
