The Suez Crisis happened in July of 1956. The basic idea is that Egypt "nationalized" the Suez Canal. That means that they took it from the company that ran it and made it property of the Egyptian government. They did this because they were mad that the US had backed out of loaning them money to build the Aswan High Dam. France and Britain, along with Israel, essentially attacked Egypt and took the canal back.
The reason that this is important is that the United States did not back the three countries that invaded, even though they were all our allies. Instead, the US was worried that this would get out of hand and lead to a war with the Soviet Union. So the US forced the three invading countries to pull out and return the canal to Egypt.
Suez Canal is an artificial waterway in Egypt that extends about 190 kilometres joining the Mediterranean and Red seas. The canal stretches north and south across the Isthmus of Suez, between the cities of Port Said and Suez. Suez Canal Crisis refers to sequence of events following nationalization of Suez Canal by Egypt on July 26, 1956, Egyptian president, Gamal A. Nasser, did this in retaliation for the withdrawal of finance by the United Kingdom (UK) and the United States for the construction of the Aswan High Dam. In retaliation the UK, and France invaded Egypt October 1956. There was no decisive victor in the war and the invaders were forced to withdraw under international pressure.
The UK and France fearing that Egypt, under leadership of Nasser might close the canal to shipments of petroleum between the Persian Gulf and Western Europe, secretly planned a joint military action to depose Nasser. Also there were conflicts between Egypt and Israel, due to which Egypt denied Israel access to Suez Canal. In retaliation on October 29, 1956 Israel invaded Egypt and advanced toward the canal. The UK and France demanded that both Israel and Egypt withdrew from the canal in response to a cease-fire ordered by the United Nations, and France put an invasion fleet to sea.
France and UK troops attacked Egypt on October 31. They captured Port Said and Port Faid, two large ports in the canal zone. There were strong objections from the United States and the Soviet Union, considering this an attempt at colonialism. The United Nations and the Soviet Union threatened armed intervention, and the United States warned of the possibilities of a nuclear confrontation between the Soviet bloc and Western countries. Under these pressures the French and UK forces withdrew on December 22 , 1956. Israeli forces withdrew subsequently in March 1957.