The Suez Crisis was precipitated by Egyptian President Gamal Abdel Nasser’s decision in July 1956 to nationalize the 120-mile Suez Canal, which had been jointly controlled by Great Britain and France, in part to fund construction of the Aswan Dam across the Nile River, a project that Western countries had refused to finance. More than two-thirds of the oil used by Europe flowed through the strategically vital waterway connecting the Mediterranean and Red Seas, and British Prime Minister Anthony Eden vowed to reclaim the “great imperial lifeline.”

France, which objected to Nasser’s support of rebels in its colony of Algeria as well as the seizure of the canal built under Frenchman Ferdinand de Lesseps in 1869, and Israel, which had engaged in sporadic battles with Egypt along their shared border, joined Great Britain in a tripartite invasion that began on October 29, 1956, when Israeli armed forces attacked the Sinai Peninsula. Two days later, under the guise of protecting the canal, Anglo-French forces began bombing Egyptian targets. On November 5, British and French paratroopers and marines began to occupy strategic positions in the canal zone.

The United Nations quickly passed a resolution calling for a cease-fire, and in a rare instance of Cold War alignment, both the United States and the Soviet Union pressured Great Britain, France and Israel to withdraw. The Soviet Union, which had supplied arms and money to Egypt, made ambiguous—and ominous—threats about using nuclear weapons to aid its ally, while the United States wielded its economic power. Furious at not being informed of the attack in advance and fearful of a wider war in the Middle East, President Dwight D. Eisenhower threatened its NATO allies and Israel with sanctions if they did not draw back their forces.

British and French troops departed Egypt in December 1956, and weeks later Eden resigned his office. Following Israel’s withdrawal in March 1957, Egypt reopened the canal to commercial shipping. The Suez Crisis made clear that the old colonial powers, Great Britain and France, had been supplanted as the world’s preeminent geopolitical forces by the United States and Soviet Union.

READ MORE: Cold War History