In the middle of the piazza is an Egyptian obelisk of Sety I (later erected by Rameses II) from Heliopolis. The obelisk, known as the Flaminio Obelisk or the Popolo Obelisk, is the second-oldest and one of the tallest obelisks in Rome.The obelisk was brought to Rome in 10 BC by order of Augustus and originally set up in the Circus Maximus. It was re-erected here in the piazza by the architect-engineer Domenico Fontana in 1589 as part of the urban plan of Sixtus V.