This Day in Military History

10 May 1969: As part of Operation Apache Snow, battalions of the 101st Airborne, the 9th Marine Regiment, and battalions of the ARVN 1st Infantry Division were sent to Dong Ap Bia mountain (Hill 937) in the A Shau Valley, South Vietnam, to take out an encampment of the North Vietnamese—the beginning of the ferocious Battle of Hamburger Hill that lasted 11 days.

Brandus, Paul. This Day in U.S. Military History (p. 121). Bernan Press. Kindle Edition.