30-acre natural area home to many rare and en-dangered plants; also sanctuary for golden-cheeked warbler and other birds. Two ecosystems: Upper half grassland savannah with wildflower meadows and stands of ashe juniper and live oak; lower half created millions of years ago by collapse of roof of an immense limestone cave now flourishing as a natural terrarium canopied by giant cypress trees. Tours limited to first 30 visitors, no reservations. About 45 minutes west of Austin. Take Texas 71 one mile past Bee Cave; left on F.M. 3238 17 miles. First gate on right after crossing Pedernales River.