Saudi Arabia’s proposed Kingdom Tower will rise to 5,280 feet. That’s a full mile. If completed, this building in Jeddah will cost $30 billion to build and will contain apartments, hotel rooms, and offices in its 12 million cubic feet of space. The graphic compares the structure to the Petronis Tower (center) in Malaysia and the Empire State Building (left) in the US. Currently, the tallest building in the world is Dubai's Burj Khalifa, which is 2,700 feet tall.