Britain's Queen Elizabeth meeting with former IRA commander Martin McGuinness today saw the latest politcal handshake.
Here is a look at some of the other significant handshakes of the last 40 years:
February 1972 - Richard Nixon makes the first visit by a US president to China, symbolically ending decades of hostility by shaking hands with Premier Zhou Enlai.
March 1979 - Israeli Prime Minister Menachem Begin and Egyptian President Anwar Sadat shake hands at the White House to seal the first peace treaty between Israel and an Arab country.
December 1989 - South African anti-apartheid leader Nelson Mandela leaves jail temporarily to meet President FW de Klerk, their handshake marking the beginning of the end of apartheid rule.
June 2000 - The leaders of communist North Korea and capitalist South Korea meet for the first time since Korea was separated in 1948, as Kim Jong-il and Kim Dae-jung shake hands.
March 2004 - British prime minister Tony Blair seals Libya's return to the world community with a handshake with Muammar Gaddafi (above).
April 2005 - Taiwanese opposition leader Lien Chan closes the book on decades of enmity by shaking the hand of Chinese President Hu Jintao in Beijing's Great Hall of the People.
