27 December 1956
5,580 Egyptian prisoners of war were exchanged for four Israelis held by Egyptian troops following the Tripartite Invasion (Israel, Britain and France). The invasion of Egypt by the three aforementioned countries began on 28 October 1956, when Israeli troops crossed the frontier into the Sinai Peninsula, allegedly to attack and destroy the bases of Egyptian commandos. The first signal of conspiracy between Israel and Britain and France came on the same day when the Anglo-French ultimatum was handed to Egypt and Israel before Israel had even reached the canal. This War (Tripartite Invasion) was one of the most important events in the history of African independence. The fallout from this unsuccessful attempt by Britain, France, and Israel to maintain an influence over the Suez Canal created a climate in Africa which both encouraged and escalated the struggle for independence.
References

Boddy-Evans A. ‘This Day in African History: 27 December’, From About African History, [online], available at www.africanhistory.about.com (Accessed: 25 October 2012)|

Godlike Production, ‘1956 Israeli Sneak Attack On Egypt, British and French Backed’,From: Godlike Production, [online], available at www.godlikeproductions.com(Accessed: 25 October 2012)|

Becker R. (2006), ‘A turning point in the Middle East balance of forces: The 1956 Suez War’, from Liberation, 01 November, [online], available at www.pslweb.org (Accessed: 25 October 2012)