President Ronald Reagan shakes hands at his first meeting with Soviet leader Mikhail Gorbachev, in Geneva, November 1985. The two leaders met for the first time to hold talks on international diplomatic relations and the arms race.
President Reagan and Soviet President Mikhail Gorbachev sign the Intermediate-Range Nuclear Forces (INF) treaty in the White House in 1987. REUTERS/File
U.S. President George H. W. Bush and Soviet President Mikhail Gorbachev shake hands in front of U.S. and Soviet flags at the end of a press conference in Moscow, July 1991. REUTERS/Rick Wilking
Mikhail Gorbachev, soviet Politburo member poses with British PM Margaret Thatcher in London, December 1994. REUTERS/Stringer
Soviet leader Michail Gorbachev and his wife Raisa with former President Reagan and Nancy, at the Reagan ranch in the Santa Ynez mountains near Santa Barbara, May 3, 1992. REUTERS/Blake Sell
President Reagan and Soviet President Mikhail Gorbachev shake hands after their mini-summit meeting in Reykjavik, October 1986. REUTERS/Denis Paquin
Pope John Paul II meets former Soviet President Mikhail Gorbachev at a private audience at the Vatican, November 2000. REUTERS/Luciano Mellace
Soviet leader Mikhail Gorbachev and Cuban leader Fidel Castro wave from an open top car as it drives through Havana's Revolution Square, April 1989. REUTERS/Files.
Former Soviet President Mikhail Gorbachev addresses students as he visits the International University in Moscow, February 2012. REUTERS/Denis Sinyakov
Soviet President Mikhail Gorbachev and President Ronald Reagan begin their mini-summit talks in Reykjavik, October 1986. REUTERS/Mal Langsdon
Nancy Reagan and Raisa Gorbachev hold scrolls during the cornerstone unveiling for a new museum at the headquarters of the International Committee of the Red Cross in Geneva, Switzerland, November 20, 1985 REUTERS/Nick Didlick
Former Soviet leader Mikhail Gorbachev and his wife Raisa pose with traditional Peking Opera singers in Taipei, March 1994.
Former Soviet leader Mikhail Gorbachev blows on candles during a ceremony ahead of his 70th birthday in Moscow, February 2001. REUTERS/Files
Then-Finnish President Mauno Koivisto (L) looks on as then-Soviet President Mikhail Gorbachev talks to Moscow on a Nokia Mobira Cityman cellular phone in Helsinki, October 1989. Markku Ulander/Lehtikuva
President Ronald Reagan stands with Soviet leader Mikhail Gorbachev during Gorbachev's arrival ceremony at the White House, December 1987. REUTERS/Gary Hershorn
President Reagan and Soviet President Mikhail Gorbachev have a few final words after a marathon meeting to conclude their mini-summit in Reykjavik, October 1986. REUTERS/Denis Paquin
Mikhail Gorbachev visits the former Berlin Wall border crossing point Checkpoint Charlie, in Berlin, November 2014. REUTERS/Hannibal Hanschke
President Ronald Reagan and his wife Nancy listen to Soviet leader Mikhail Gorbachev speak during Gorbachev's departure ceremony at the White House, December 1987. REUTERS/Gary Hershorn
A four-way handshake between (L-R) Soviet Foreign Minister Eduard Shevardnadze, Soviet leader Mikhail Gorbachev, President Reagan and U.S. Secretary of State George Schultz in Geneva, Switzerland, November 21, 1985. REUTERS/Denis Paquin
Soviet leader Mikhail Gorbachev meets with President Reagan in Geneva, November 19, 1985. REUTERS/Denis Paquin
Former U.S. President George Bush gestures ahead of a meeting with former Soviet leader Mikhail Gorbachev in Berlin November 1999. REUTERS/Files
Former U.S. President Ronald Reagan takes former Soviet President Mikhail Gorbachev for a drive in his Jeep to tour the Reagan ranch in the Santa Ynez mountains near Santa Barbara, California, May 1992. REUTERS/Files
Cuba's President Fidel Castro and Soviet leader Mikhail Gorbachev during an event in Havana, April 1989. REUTERS/Gary Hershorn
President Reagan and Soviet President Mikhail Gorbachev leave Hofdi House after finishing their two days of talks during a mini-summit in Reykjavik, October 12, 1986. REUTERS/Nick Didlick
Former U.S. President George Bush hugs former Soviet leader Mikhail Gorbachev ahead of a reception in Berlin to mark the 10th anniversary celebrations of the collapse of the Berlin Wall, in 1999.
Cuba's President Fidel Castro and Soviet leader Mikhail Gorbachev exchange documents during a treaty signing ceremony in Havana, April 1989. REUTERS/Gary Hershorn
Former Soviet president Mikhail Gorbachev looks on during a presentation of his new book "After Kremlin" in Moscow, December 2014. REUTERS/Sergei Karpukhin
Former German Chancellor Kohl, former Soviet Union President Gorbachev and former U.S. President Bush wave during the 'Point Alpha Award' ceremony near the village of Geisa in eastern Germany June 2005. REUTERS/Fabrizio Bensch
Former Soviet president Mikhail Gorbachev attends a parade marking the World War II anniversary in Moscow, May 2017. REUTERS/Sergei Karpukhin
Former Soviet leader Mikhail Gorbachev reaches out to touch the casket containing former U.S. President Ronald Reagan, as Reagan lies in state at the U.S. Capitol Rotunda, June 2004. REUTERS/Mike Segar
Former Soviet president Mikhail Gorbachev smiles during a news conference marking the 20th anniversary of Perestroika at the U.S. Chamber of Commerce in Washington, October 2005. REUTERS/Files