Pergamon was established in the 3rd century BC as the capital of the Attalid dynasty. Situated in the Aegean Region, at the intersection of Europe and the Middle East, it developed into a significant cultural, scientific, and political hub. The monuments in Pergamon are exceptional, including the steep theatre, lengthy stoa, three-terraced Gymnasium, Great Altar of Pergamon, tumuli, pressured water pipelines, city walls, and Kybele Sanctuary, which was perfectly aligned with Kale Hill. As the Attalid capital, Pergamon protected cities during the Hellenistic Period and held political and artistic power, building intense relationships with contemporary civilizations. The Attalid Dynasty founded one of the largest libraries in Pergamon. Additionally, they created the famous sculpture school due to the rivalry between three Hellenistic dynasties. After the city was passed to the Romans in 133 BC, Pergamon became a metropolis and served as the capital of the Roman Province of Asia during the Roman imperial period. During the Roman Period, the Romans preserved the existing structures of the Hellenistic Period while adding new functions as a cultural and imperial cult centre of the empire. As a result, many important structures were built or further developed, including the Asclepion Sanctuary, a well-known healing centre whose sacred spring still flows; the Roman Theatre; one of the largest Roman amphitheatres; a great aqueduct; the Trajan Temple and the Serapeum. During the Byzantine Period, Pergamon underwent a transformation from a major Hellenistic and Roman centre to a middle-sized town due to the relocation of trade roads and political centres from the Aegean Region to northwest Anatolia, particularly Istanbul. Despite this change, Pergamon retained its cultural and religious significance as the home of one of the Seven Churches of Asia. Following the Ottoman arrival, Pergamon underwent further cultural adjustments, which are particularly evident on the Bakırçay Plain. The Ottomans provided the city with essential urban structures, including mosques, baths, bridges, khans, bedestens (covered bazaars), arastas (Ottoman markets), and water systems that overlaid the Roman and Byzantine settlement layers. The re-use of structures by later cultures is exemplified by the Church of St. John, which was previously part of the Serapeum, a sanctuary dedicated by the Romans to an Egyptian deity. The building was later converted into an Ottoman Mosque and also served as a Jewish Synagogue. From the 3rd century BC onwards, Pergamon was encircled by a ring of grave mounds of various sizes, which demonstrated its claim to the plain of Bakırçay. In addition to grave mounds, there were sanctuaries, such as the Kybele Sanctuary at Kapıkaya, sited on prominent hills and mountain peaks in the area surrounding the city. Pergamon is a testimony to the unique and integrated aesthetic achievement of the civilizations. The site incorporates structures from Hellenistic, Roman, Byzantine, and Ottoman periods, reflecting the cultural influences of Paganism, Christianity, Judaism, and Islam. The preservation of these cultural features within the historical landscape is noteworthy. Pergamon and its Multi-Layered Cultural Landscape have been on the UNESCO World Heritage List since 2014.