Soltaniyeh, located some 240 kilometres (150 mi) to the north-west of Tehran, was built as the capital of Mongol Ilkhanid rulers of Iran in the 14th century. Its name which refers to the Islamic ruler title sultan translates loosely as "the Regal". Soltaniyeh was visited by Ruy González de Clavijo, who reported that the city was a hub of silk exportation.[1]

In 2005, UNESCO listed Soltaniyeh as one of the World Heritage Sites. The road from Zanjan to Soltaniyeh extends until it reaches to the Katale khor cave.

William Dalrymple notes that Öljaitü intended Soltaniyeh to be "the largest and most magnificent city in the world" but that it "died with him" and is now "a deserted, crumbling spread of ruins."[2]