A 25,000-year-old Ice Age structure made from the bones of 60 woolly mammoths has been unearthed in Russia. This is not the first "mammoth house" found in Russia, but it is the oldest and largest. Since 2014, a team of scientists has been excavating the 40-foot-wide circular bones at a Paleolithic site about 300 miles south of Moscow. The structure includes several walls, fire pits, and areas for butchering.