What day of the week was June 6, 1971?

The day of the week June 6th, 1971 fell on was a Sunday.

Soyuz program: Soyuz 11 is launched. A midair collision between a Hughes Airwest Douglas DC-9 jetliner and a United States Marine Corps McDonnell Douglas F-4 Phantom II jet fighter near Duarte the California, claims 50 lives. Vietnam War: the Battle of Long Khanh between Australian and Vietnamese communist forces begins.