The Salt Palace in Grand Saline, Texas is the only building in the U.S. made entirely of rock salt. The town, founded in 1845, sits on top of a 16,000-foot-deep salt deposit that is still mined by Morton. The deposit is expected to last 20,000 years.
This is actually the third Salt Palace built in Grand Saline. The first building was torn down, and the second building melted. But the current Salt Palace, built in 1993, has an overhanging roof to protect it from the elements.
Visitors to the Salt Palace will learrn about salt mining and the history of Grand Saline, including a display about the town's most famous son, Wiley Post, who in 1931 became the first person to circle the globe in an airplane.