The Sunnydale Natural History Museum was the local museum in Sunnydale.
History
In 1997, under the banner "CULTURAL EXCHANGE SPECIAL EXHIBIT: TREASURES OF SOUTH AMERICA", one of its acquisition, was a Inca Mummy.
In 2001, the Trio steal a diamond to run the Freeze Ray, testing it on Rusty, the museum guard.
It was presumably destroyed along with the rest of Sunnydale by following the Battle at the Hellmouth.