The largest hotel in the world, with a staggering 10,000 rooms is currently under construction in Saudi Arabia. Twelve towers, 10,000 rooms and 70 restaurants, plus helipads and a full-size convention center: That's the plan for Abraj Kudai, a complex in Mecca, Saudi Arabia, that's set to become the world's largest hotel by room count when it opens. Designed by architectural firm Dar Al-Handasah, the $3.5 billion site is currently under construction and will stretch across 1.4 million square meters.