First UN peacekeeping force UNEF was employed?

In the Sinai, in response to the Suez Crisis (a joint Israeli-British-French invasion after the Egyptian government threatened to close off the Suez Canal), from November 7 of 1956 until the Egyptian government ordered UN forces out of the Sinai on May 16th, 1967 (although the last of the UNEF forces didn't leave until June 17th).