The remains of the ancient town can be visited
Terme di Diocleziano

In Rome, the Baths of Diocletian were once one of the largest bathing complexes of ancient Rome. They accommodated thousands of bathers simultaneously.
History+
The construction of the Baths of Diocletian took place between 298 and 306 AD and is said to have required the labor of 40,000 slaves. Spanning 376 by 361 meters, they could accommodate up to 3000 bathers. In 537, the Goths ended the bathing operations by destroying the Roman aqueducts. The decaying structures were subsequently used for various purposes, partly as a quarry.
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This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 41.9031, 12.4968