Many Romans detest Richard Meier's minimalist glass-and-marble pavilion (the first modern construction in Rome's historical centre since WWII), but it is no longer likely to be completely pulled down, as Mayor Gianni Alemanno had promised on his election in 2008. However, the wall dividing the busy Lungotevere Augusta from Piazza Augusto Imperatore – which has been criticised for obscuring the baroque facade of the church of San Rocco all'Augusteo – is to be dismantled, according to new plans approved by the architect.

Inside is the less-controversial Ara Pacis Augustae (Altar of Peace), Augustus' great monument to peace. One of the most important works of ancient Roman sculpture, the vast marble altar (it measures 11.6m by 10.6m by 3.6m) was completed in 13 BC and positioned near Piazza San Lorenzo in Lucina, slightly to the southeast of its current site. The location was calculated so that on Augustus' birthday the shadow of a huge sundial on Campus Martius would fall directly on it. Over the centuries the altar fell victim to Rome's avid art collectors, and panels ended up in the Medici collection, the Vatican and the Louvre. However, in 1936 Mussolini unearthed the remaining parts and decided to reassemble them in the present location.

Of the reliefs, the most important depicts Augustus at the head of a procession, followed by priests, the general Marcus Agrippa and the entire imperial family.