Aya cave is the biggest among all caves of Aya bay. It amazes by its passage branching, which are decorated with wandering limestone formation and calcite crystals. Descent to this cave is like a crater. The cave is being worshiped by buryat-shamanists since ancient time. People used to throw coins and other items as donations to "Master of the mountain". At the top of the rock public shaman rituals - "taylagans" were performed. There are a lot of legends about this cave. Rock drawings carved on near-by rocks show people and different animals. These drawing are more than 2500 years old.