Built on mid 17th century, Nizwa Fort is most visited the national monument in Oman. A 45-minute drive from Jebel al Akhdar, this fort is nowadays overwhelmed by visitors enjoying architecture from Ya’rubi era. Hudge cylindric tower is the main part of this fortification. it stands 30 meters tall and 36 meters wide. Sistem of water supply and underground food and ammunition cellars made possible for a fort to survive long sieges.