Today we hiked down into the natural entrance to Carlsbad Caverns. Cave swallows dived and twittered and fed their young in the huge rock faces leading down to the dark opening.

We hiked down into the subterranean depths, walking by the branch of Carlsbad that leads to the Bat Cave, where the colony of Mexican free-tails spends the summer months. The branch-off is in what they call the "twilight zone" of the cave, where enough natural light still filters in for one to see without a flashlight. Here we veered off, heading down, down, 750 feet under the earth.

It's hard to express the sheer immensity of the cave -- the deep silence and stillness broken only by the occasional drip or trickle of water; the chill air, alive with moisture, and the wonder of the many glistening and strange formations. I imagine growing up in a cave, never seeing the outside, and how alien the upstairs world would seem -- beyond imagining while down in those dark depths, navigating narrow paths between cave pools and towering columns. The thought of a sunlit, grassy world with mountains and trees and a vast blue sky would seem like a fantasy world.

Thinking of morlocks, I descended farther, seeing strange faces in the formations. Apparently I'm not the only one, though - the so-called Whale's Mouth is one of the coolest formations we encountered. Looking up at it from a lower point in an absolutely gigantic open room, I could clearly see a behemothic baleen whale, lips parted and eye glistening, trolling for prey.

After passing through one of the tallest sections of the cavern, we entered the stunning Green Lake Room and just stood in awe of all the stalactites, columns and draperies.

After leaving the cave, we opted to participate in the Adopt-A-Bat program in the park, which gives money to support research to protect bats and encourage education about our chiropteran friends.

We drove farther west, reaching Guadalupe Mountains National Park just before dusk. Birds sang and flew from bush to bush -- goldfinches, mockingbirds. Rabbits munched their dinners. I don't know if you've seen the film Night of the Lepus, about giant killer rabbits rampaging through the desert southwest, but the rabbits I snapped a picture of may be related...eeeek!

Another gorgeous sunset, this time over the Guadalupe Mountains, left us in awe.

Tomorrow...on to the Sonoran Desert and those famous cacti, the saguaro.