Mausoleum of Maxentius
Rome, Italy
The Mausoleum of Maxentius was part of a large complex on the Appian Way in Rome that included a palace and a chariot racing circus, constructed by the Emperor Maxentius. The large circular tomb was built by Maxentius in the early 4th century, probably with himself in mind and as a family tomb. When his young son Valerius Romulus died, he was buried there. After extensive renovation the mausoleum was reopened to the public in 2014.
Monument data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).