Its the original and Natural Bridge Caverns most popular tour, the Discovery Tour introduces you to an underground world of natural beauty and amazement. Travel through a half-mile of the largest and most spectacular show cavern in Texas. You ll walk 180 feet below the ground, while listening to our knowledgeable tour guide. See awe-inspiring, ancient formations centuries in the making and still growing today, such as amazing stalagmites, stalactites, flowstones, chandeliers and soda straws. Departs every 40 minutes, or sooner throughout the day Tour duration: 75 minutes; Walking distance: 3/4 mile. Fee: 12 and older $19.99; ages 3-11 $17.99. Open daily except Thanksgiving; Christmas and New Years Day. Fee