Gonbad-e Qabus tower is a monument in Gonbad-e Qabus, Iran, and a UNESCO World Heritage Site since 2012.The Tower in the central part of the city reaches 72 metres (236 ft) (including the height of the platform).The baked-brick-built tower is an enormous decagon building with a conic roof, which forms the golden ratio Phi, that equals 1.618.