Which U.S. national park in New Mexico is famous for its Big Room limestone chamber?

Carlsbad Caverns is the New Mexico national park famous for its Big Room limestone chamber.

Carlsbad Caverns National Park lies in southeastern New Mexico and protects an extensive underground cave system formed in the ancient reef of the Capitan Reef complex. Sulfuric-acid-rich groundwater helped dissolve the limestone, creating the cavern’s passages, chambers, stalactites, stalagmites, and other formations.

The Big Room, also called the Hall of the Giants, is the best-known chamber. Its floor covers about 357,000 square feet, making it the largest chamber in Carlsbad Caverns and one of the largest underground chambers in North America. Visitors can reach it by descending through the natural entrance or by using the visitor-center elevators.

The park was established in 1930 and became a UNESCO World Heritage Site in 1995. It is also famous for the evening flight of Brazilian free-tailed bats from the cavern entrance. Great Basin, Mammoth Cave, and Wind Cave are also cave-associated parks, but none is the New Mexico site identified by the Big Room.