Ice caves can occur in glaciers.
Lava caves form when molten rock flows from an erupting volcano, creating tubes or passageways that remain after the lava drains away. A water-filled, often perfectly round sinkhole found in the Yucatan jungle. The ancient Maya feared the cenotes, believing they were sacred gateways to an underworld inhabited by dark spirits. Most of the world's caves are limestone caves. The Museum is open to the public seven days a week, closing only Thanksgiving Day, Christmas Eve, and Christmas Day.