The tropical climate at the time led to the formation of large reefs made of ... formations in the Carlsbad Caverns — including soda straws, draperies, lily pads, cave pearls and cave popcorn.

Today, visitors can take a 75-minute walking tour through the 64-degree cave, home to the Ozarks’ longest soda straw formation and two bottomless lakes. The remaining caves in northern Arkansas ...