The Waco siege, also known as the Waco massacre, was the siege by law enforcement of the compound that belonged to the cult known as the Branch Davidians, led by David Koresh between February 28 and April 19, 1993 at Mt. Carmel Center ranch in Axtell, Texas.

What began as an attempt to serve a search and arrest warrant by the ATF (Bureau of Alcohol, Tobacco, Firearms and Explosives) resulted in an intense 51 day siege and the deaths of 76 Branch Davidians, including 25 children, two pregnant women, and David Koresh himself.

Sources:

Jim McGee and William Claiborne : The Washington Post ,1993
The Waco Siege: An American Tragedy : Dwayne Walker and Jack Rosewood,
Witness to Waco : MSNBC News
A Place called Waco : David Thibodeau