Pulacayo is a former silver-mining settlement east of Uyuni, best visited as a short historical detour from town. Its claim to fame is Bolivia's first railway, built to move ore from one of the world's great silver mines, and the remains of the train said to have been robbed by Butch Cassidy and the Sundance Kid.
The site is rough-edged rather than polished, but that is part of the appeal. Go for mining history, railway relics, and a clearer sense of the industrial world that made Uyuni more than just the gateway to the salt flat.