Baths of Diocletian

The largest of the imperial bathing complexes in ancient Rome, these baths were completed around 306 AD and could accommodate thousands of visitors at once. Much of the surviving structure was later repurposed: Michelangelo converted the central frigidarium into the church of Santa Maria degli Angeli, and other halls now form part of the National Roman Museum. The grand vaulted spaces convey the immense scale of Roman engineering, with towering brick and concrete walls.