My favorite part of the trip from Austin to Marathon, is the drive on US 385 through the Sierra Madera Astrobleme between Fort Stockton and Marathon. An astrobleme is the eroded remnant of a large meteorite crater. This one is about 6 - 8 miles in diameter and US 385 provides a rim to rim trip, with the 4583 foot central peak just to the east. The surrounding desert is about 3500 feet. It is estimated to be less than 100 million years old.

The crater rims are well marked along the highway.

This Google Maps based image makes the overall crater structure clear. Base map copyright 2008 Google.

Learn more about the Sierra Madera Astrobleme from the University of Texas of the Permian Basin.