Roman Thermae

The well-preserved ruins of Varna's 2nd-century-AD Roman Thermae are the largest in Bulgaria and the fourth-largest of their kind in Europe. Visitors are allowed to clamber around the various chambers of the bath complex and admire surviving pieces of the advanced floor- and water-heating systems. The baths survived in their original form for only a century or two before the complex was abandoned. It was too costly to maintain as the empire began to decline.