The Waco Mammoth National Monument is a paleontological site and museum in Waco, Texas, United States where fossils of 24 Columbian mammoths and other mammals from the Pleistocene Epoch have been uncovered. The site is the largest known concentration of mammoths dying from a reoccurring event, which is believed to have been a flash flood. The mammoths on site did not all die at the same time but rather during three separate events in the same area.