Fodor's Expert Review Mercer Caverns

Lighthearted, well-informed guides lead 45-minute tours (208 steps down, 232 steps up) into caverns a prospector named Walter J. Mercer discovered in 1885. Millions of years in the making, the sheer, draperylike formations and aragonite crystals that resemble snowflakes are enthralling. Dress in layers (even in summer) and wear nonskid closed-toe shoes for this mildly strenuous adventure.