After the United Kingdom and the United States withdrew their pledge to support the construction of the Aswan Dam due to Egyptian overtures towards the Soviet Union, Egyptian President Gamal Abdel Nasser nationalised the canal in 1956 and transferred it to the Suez Canal Authority, intending to finance the dam project using revenue from the canal, while at the same time closing the Gulf of Aqaba to all Israeli shipping by closure of the Straits of Tiran. This provoked the Suez Crisis, in which the UK, France and Israel hatched a plan to invade Egypt. The intention was for Israel to invade on the ground, and for the Anglo-French partnership to give air and other support, later to intervene to resolve the crisis and control the canal. 

To stop the war from spreading and to save the British from what he thought was a disastrous action, Canadian Secretary of State for External Affairs, Lester B. Pearson, proposed the creation of the very first United Nations peacekeeping force to ensure access to the canal for all and an Israeli withdrawal from the Sinai. On 4 November 1956, a majority of nations at the United Nations voted for Pearson's peacekeeping resolution, which mandated the UN peacekeepers to stay in the Sinai Peninsula unless both Egypt and Israel agreed to their withdrawal. The United States backed this proposal by putting financial pressure on the British government, which then agreed to withdraw its troops. Pearson was later awarded the Nobel Peace Prize.

As a result of damage and ships intentionally sunk under orders from Nasser the canal was closed until April 1957, when it was cleared with UN assistance. A UN force (UNEF) was established to maintain the neutrality of the canal and the Sinai Peninsula.

Suez Crisis
Timeline
Arab-Israeli wars of 1967 and 1973
Receding Red Sea and the dwindling Nile