LONDON (AP) - Queen Elizabeth II and former Provisional Irish Republican Army leader Martin McGuinness are expected to shake hands in a delicately choreographed moment for both sides, an encounter which may be shielded from cameras but which puts a further seal on the peace process in Northern Ireland.
Here's a gallery of historic handshakes that became powerful symbols of peace:
U.S. President Richard Nixon, a staunch anti-Communist through much of his political career, shakes hands with Chinese Communist leader Mao Zedong in February 1972 on Nixon's historic visit to China.
Israeli Prime Minister Menachem Begin welcomes Egyptian President Anwar Sadat with a handshake on Nov. 19, 1977, an extraordinary gesture that helped lead to the signing of a peace treaty 16 months later.
A handshake between U.S. President Ronald Reagan and Soviet Premier Mikhail Gorbachev on Nov. 19, 1985 at a summit in Geneva signals the opening of a new era in relations.
President F.W. de Klerk and Nelson Mandela shake hands in Cape Town, South Africa on May 4, 1990 after announcing an agreement on steps that will lead to talks on ending white-minority rule.
Israel Prime Minister Yitzhak Rabin and Palestinian leader Yasser Arafat shake hands in public for the first time at the White House on Sept. 13, 1993, with President Bill Clinton looking on. The agreement called for a final settlement to be achieved by February 1999.
(Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)