The temple was built as a 'serapeum' to introduce Egyptian mystery cults to the Roman city of Pergamum.
Engineers diverted the local river through two massive, 196-meter-long stone tunnels beneath the temple courtyard.
The structure features two side towers that are still visible, which were once flanked by statues of Egyptian gods.
The massive walls were originally clad in colorful marble veneer that has since been stripped or lost to time.
During the Byzantine era, the central hall was divided into a basilica layout, transforming the pagan temple into a Christian church.
It is considered one of the 'Seven Churches of Asia' mentioned in the Book of Revelation.
The mortar used in the brickwork is exceptionally thick, a signature technique of Roman construction in this region.
The site contains large monolithic columns that are among the largest ever carved in the Roman world.
The Red Hall Basilica, known as Kızıl Avlu in Turkish, is a massive Roman temple complex built during the 2nd century AD under Emperor Hadrian. Constructed primarily of red brick, it was originally dedicated to the Egyptian gods Isis, Serapis, and Harpocrates. The site is notable for its immense dimensions, with the main structure measuring approximately 60 by 26 meters. Its architectural design incorporates hidden subterranean channels and side towers that remain largely intact today. In the Byzantine period, the structure was converted into a church dedicated to St. John the Apostle, featuring an apse added during this transformation. The complex stands as one of the largest surviving Roman brick structures in the world. Its foundations were partially constructed over the Selinus River, which was diverted through a complex system of tunnels beneath the building.
From the south courtyard, looking up at the towering red brick walls that frame the sky.
Explore the side wings where small sections of original wall frescoes and floor mosaics can still be discerned.
Walk around the exterior to see the sophisticated subterranean vaulting and river tunnel entrances.
Visit during the shoulder season to avoid the intense heat reflecting off the red brick surfaces.
Do not attempt to climb onto the loose masonry or enter the restricted subterranean tunnels for safety reasons.
Maintain a respectful tone as the site contains remnants of both Roman temple architecture and Christian basilica structures.
