This temple was built on a monumental scale and is one of the largest Roman temples known. Dedicated to Jupiter Heliopolitanus, it was built from the 1st century BC onwards on an immense substructure more than 90m long. Though largely ruinous, it impresses by its sheer size.
At the entrance, a staircase leads to a propylaea (entrance) that gives on to an unusual hexagonal courtyard, a 2nd-century-AD addition. Beyond here is the massive central courtyard, with two high altars flanked by ritual columns in grey and pink granite. Another enormous staircase led from here to the temple itself, consisting of a cella in which the statue of the god was housed and a surrounding portico of 10 columns along the facade and 19 columns along the side. These columns are the largest known from antiquity – 22.9m high with a girth of 2.2m. Today only six of these remain standing with the architrave still in position.
It was probably built over an earlier Phoenician temple and, as was common in antiquity, the 'Sun City' Jupiter preserved some solar and cosmic attributes of Ba'al, the deity he was superseding.
