Originally built as the Thysdrus, this town in northern Africa features well-preserved architecture from the days of the Roman Empire. El Djem was once the second-most important city in the region, behind Carthage, and its most famous feature is a massive amphitheater, constructed in the third century, which could house up to 35,000 spectators. Though parts of the structure have crumbled, enough of it still stands to conjure its former glory. The town is also home to a museum that features a large selection of mosaics and a restored Roman villa.