More than 1,000 years ago, Indigenous people journeyed into a dark cave on the land now called Missouri and painted nearly 300 detailed images on its walls.
The cave was a sacred space, where tribes performed ceremonies, made sense of the universe and buried their dead. A millennium later, the paintings contained within it continue to offer clues about how those civilizations lived and what they believed.
On Tuesday, Picture Cave -- as it's commonly known -- sold at auction for $2.2 million. And for the Osage Nation, whose ancestors created much of the artwork in the cave, the sale came as a huge blow.