Pergamon
Pergamon's other notable structure is the great temple of the Egyptian gods Isis and/or Serapis, known today as the "Red Basilica" (or "Kızıl Avlu" in Turkish), about south of the Acropolis at (39 7' 19" N, 27 11' 1" E). It consists of a main building and two round towers within an enormous "temenos" or sacred area. The temple towers flanking the main building had courtyards with pools used for ablutions at each end, flanked by stoas on three sides. The forecourt of the Temple of Isis/Sarapis is still supported by the Pergamon Bridge, the largest bridge substruction of antiquity.
Pergamon Altar
Already Attalos I began to remodel the acropolis of Pergamon. In the course of time the original structures were augmented by a Dionysus temple, a theater named after Dionysus, a heroon, an upper agora for the city, and the great altar known today as the Pergamon Altar. There were also several palaces, and a library in the Athena sanctuary.