Home of the 'Ultra Americans'.
The United States had its own code-breaking centers. The army worked out of Arlington Hall in northern Virginia, and the navy had facilities in Washington, DC, and Dayton, Ohio. None of these is open to the public today. A traveler who wants to visit the scene of American WWII code-cracking must head to Bletchley Park. Several hundred so-called "Ultra Americans" worked with the British, including a contingent at Bletchley.
Once the estate of London banker Herbert Samuel Leon, Bletchley Park had fallen into the hands of real estate developers by the 1930s. The British government purchased it, and code-breaking operations began here in August 1939. Britain recruited its best military and civilian minds to work at Bletchley. Originally, the code-crackers toiled in the Victorian-era mansion, but as the war expanded, wooden huts and sturdier brick buildings were built on the grounds. The country estate soon took on a military appearance. This was code-breaking on an industrial scale.
Germany encrypted its field communications with the Enigma machine, whose system of rotors could scramble any message into billions of possible combinations. Unscrambling a message required a knowledge of the rotor settings, which changed daily. To encrypt higher-level messages, the Germans used the even more complicated Lorenz machine.
The Germans believed their encryptions were impenetrable, but they hadn't counted on the brilliant minds at Bletchley. In 1940, building on the work of Polish cryptographers, British mathematician Alan Turing developed the "bombe," a machine that could analyze a message and determine the Enigma rotor settings. To decipher the Lorenz machine, Bletchley's scientists developed Colossus, the world's first programmable computer, which began operation in 1944.
Britain and America started cooperating on intelligence matters after Pearl Harbor. The first American observers arrived at Bletchley in 1942, and Turing traveled to the United States to help America build its own bombes. In 1943, the US Army's 6813th Signal Security Detachment arrived at Bletchley Park. The Americans were quickly integrated into British operations. Several worked in Hut 6, which decrypted German army and air force communications. Others worked in Hut 3, which translated decrypted messages from German into English. Still others played support roles, even as cooks and drivers.
The intelligence gathered here, with the active participation of Americans, influenced the course of the war in countless ways. It shaped plans for D-Day and turned the tide in the Battle of the Atlantic. After the war, however, everyone who worked at Bletchley was sworn to secrecy. Bombes and the Colossus were destroyed to keep them out of Soviet hands. Bletchley's wartime role remained concealed from the public until the 1970s.
Today, this site that played such an important part in winning the war for the Allies is preserved as the Bletchley Park National Codes Centre. My wife and I made the short rail trip from London's Euston Station in springtime. London and its suburbs quickly gave way to green fields dotted with white sheep and yellow patches of flax.
The museum grounds are just a short walk from Bletchley Station. Visitors can take a guided tour, rent an audio guide, or explore the grounds on their own. Exhibits in Block B provide an introduction to Bletchley's wartime activities. Here one can inspect Enigma and Lorenz machines, as well as a re-creation of a bombe.
We opted for the guided tour. After an introductory talk in the mansion, we were led to some fascinating places. A cottage near the stable, we were told, was where the first German message was successfully decrypted. Hut 11 contained several bombe reproductions. Here we listened to a talk on how these machines worked. Perhaps the most interesting specimen was in Block H: a Colossus computer, rebuilt, fully functional, and filling an entire room. Standing before this massive bank of circuits and vacuum tubes, I couldn't help but reflect upon the computer revolution that began at Bletchley.
The site was neglected for years after the war. Some buildings are still in disrepair and are undergoing renovation, but many have been restored and contain exhibits about various aspects of World War II. Hut 8, for example, houses displays about the wartime use of messenger pigeons. Though not mentioned in the exhibit, the first Americans of the 6813th sailed for Europe using the cover story of being pigeon handlers in order to conceal their real mission.
The number of Americans at Bletchley was small, but the British graciously recognize their contributions. The American Garden Trail winds along a pond in front of the mansion and contains plant specimens native to North America, most notably a sequoia planted long ago by the Leon family. During the war, a radio antenna was attached to the tree's top--an indirect American contribution to Allied victory!
These grounds were also the scene of picnics and recreation for the code-crackers. On one occasion, the British challenged the Americans to a game of rounders--an English version of baseball. Though the Americans were adept at deciphering Nazi codes, they could not penetrate the mysteries of this game. When it was over, the Americans thought they had won, and were surprised to find out they'd lost.
Winston Churchill once called Bletchley's code-breakers his "geese that laid the golden eggs and never cackled." It is worth noting that some of those geese were Yanks.
LOCATION: Bletchley Park National Codes Centre is on Sherwood Drive in Milton Keynes, Buckinghamshire, England, about halfway between London and Birmingham, just off the M1 highway.
HOURS: November through March, 10:30 a.m. to 4 p.m.; April through October, 9:30 a.m. to 5 p.m. weekdays, 10:30 a.m. to 5 p.m. weekends and bank holidays. Open daily except December 24-26 and New Year's Day.
FEES: 10 [pounds sterling] for adults, 8 [pounds sterling] for seniors over 60 and students, and 6 [pounds sterling] for children ages 12-16; free for younger children. A family ticket (two adults and two children ages 12-16) is 22.50 [pounds sterling] (1 [pounds sterling] = $1.64).
INFORMATION: Call 011-44-1908-640404 (dialing from the US) or visit bletchleypark .org.uk.
Mark D. Van Ells is a history professor at the City University of New York.