Pictures: 11 Most Endangered U.S. Historic Sites Named

Bear Butte, South Dakota

Photograph courtesy Jenny Buddenborg, NTHP

At 4,426 feet (1,349 meters) tall, Bear Butte (pictured) is a sacred mountain for as many as 17 Native American tribes, including the Lakota of the Black Hills of South Dakota.

"A place of prayer, meditation, and peace, this National Historic Landmark is threatened by proposed wind and oil energy development that will negatively impact the sacred site and further degrade the cultural landscape," according to the trust's website.

Published June 23, 2011