In 1972, Richard Nixon became the first American president to visit the USSR.
Nixon meets with then-Soviet leader Leonid Brezhnev in the Kremlin.
The meeting in Moscow lasts from May 22 to May 30. Several anti-ballistic missile treaties were signed, the first Strategic Arms Limitation Treaty, and the US-Soviet Maritime Incidents Agreement.
This is considered the first part of a reconciliation between the two main Cold War rivals.
On May 29, Nixon and Brezhnev concluded the conference by signing a joint declaration on avoiding military confrontation and on disarmament.
Richard Nixon and his wife Pat were exposed to potentially harmful radiation while they were at the US ambassador's residence in Moscow in 1959, declassified Secret Service documents show, "BgVoice" recalls.
Nixon, who was vice president at the time, was not informed of the threat, and the State Department only found out in 1976, when a member of His Secret Service agent, James Golden, revealed that the equipment had measured significant levels of radiation in and around the Nixon family's bedrooms at Spaso House. Golden said he was later told by the State Department that he had been exposed to "huge doses" of ionizing radiation produced by an atomic battery used by Soviet spies to power listening devices hidden in the building.
However, the secret agent expressed doubts about this explanation, and it has not been confirmed. Now, for the first time, the original documentation has been made available online after a request to the Nixon Presidential Library by the National Security Archive at George Washington University. One of the archives' senior analysts, William Burr, who made the request, said that "this unusual and largely unknown episode of the Cold War deserves more attention so that the mysteries surrounding it can be solved."
The documents are being released as part of a series on the Soviet Union's use of various types of radiation against U.S. targets, including the exposure of the U.S. Embassy in Moscow to microwave radiation over many years. The records take on new significance in light of the current mystery surrounding Havana Syndrome, a group of mostly neurological symptoms suffered by dozens of U.S. diplomats and spies in recent years. Ionizing radiation is defined as having enough energy to damage cells and alter DNA.
Dosimeters at Spaso House during Nixon's visit measured 15 roentgens per hour. This was less than a lethal dose, but the permissible occupational exposure standard in the United States at the time was only 5 roentgens per year. After Secret Service agents exposed the Soviet dirty tricks, revealing that they had discovered the listening devices in the residence, the radiation stopped.