The Pyramid of Cestius (c. 18-12 BCE) was built as the tomb of Gaius Cestius, about whom we know absolutely nothing apart from what is stated in the dedicatory inscription.
The pyramid, which is made of concrete faced with slabs of marble, was erected at a fork of the Via Ostiensis and a road which ran to the river Tiber (roughly following the route of today's Via della Marmorata). The inscription was added to both the east and west face so that it could be seen from either road.
The pyramid, which is 37 metres (121 feet) high and in an excellent state of preservation, was built within 330 days, as another inscription states.
Pyramids of a similar size had been built for private individuals in Upper Egypt, but in Cestius’ day they were particularly popular in Nubia (Sudan), which may suggest that he had served in the province. In the late 3rd century the pyramid was incorporated into the Aurelian walls.