Located in northwestern Iran, Hamedan witnessed an intensive cultural interchange amongst civilizations since antiquity, as it served as a crucial geopolitical, cultural, and trading focal point at the gateway to the Iranian Plateau. This interchange contributed to the rich and diverse heritage of its historic centre, from its bazaar and religious buildings to its urban layout shaped by a 20th century radial city plan built over the old city. Within the city are the archaeological remains of ancient Hegmataneh. Continuously inhabited for nearly three millennia, Hegmataneh provides important and rare evidence of the Medes civilization in the 7th and 6th centuries BCE and later served as a summer capital of Achaemenid, Seleucid, Parthian, and Sasanian rulers.