Texas' Largest underground attraction. Natural Bridge Caverns is Texas' largest show cave. We offer both commercial tours (concrete trails and electric lights) and adventure-class tours (off-trail). Our commercial tours venture into different sections of the cavern. The Discovery Tour follows the path of the caverns' discoverers 1/2-mile into the cave. The Illumination Tour allows guests to explore the first three rooms of the Hidden Passages. The two adventure tours we offer also go into different sections of our cave. The Discovery Adventure Tour follows the regular Discovery Tour but then jumps off trail and goes even deeper into the cave. The Hidden Passages Adventure Tour follows the Illuminations Tour to the Cathedral Room and then continues another 1/2-mile into the cave. Both adventure tours take about 3 hours.