Roman theater of Cartagena, Spain © Luis Davilla/Getty Images
A surprising discovery was made here in the city of Cartagena in 1988 during the construction of a new shopping center. The remains of this ancient Roman theater were found buried underground, where they’d been hidden for centuries, partially covered by the city’s old cathedral. The theater has since been painstakingly restored. Archaeologists say it was constructed sometime between 5 and 1 BCE and at one time could hold up to 6,000 spectators.