Umoona Opal Mine & Museum

Coober Pedy's largest underground attraction, set in an opal mine first worked in 1916 and rediscovered in 1968 beneath the main street. The free museum runs through the opal town's history, Aboriginal and settler, its geology and its fossils, including an opalised marine reptile, with the "Story of Opal" documentary screening in an underground cinema. Guided tours descend into the original workings to a genuine opal seam. Below ground it holds 22 to 24 degrees year-round.