Built by Caracalla in the year 212, these baths covered more than 11ha and could accommodate 1 600 people at any one time. The baths were in use until 538, when the Goths damaged the aqueducts which supplied water to Rome. Today visitors can admire the ruins of the laconicum (very hot room), the gymnasia, the changing rooms (apodyterium) and the swimming pool (natatio). A virtual video guide shows visitors how the baths would have looked in 216.