Designed as a sleek glass tower built atop three legs and tapering into a skyscraping needle, Kingdom Tower in Saudi Arabia was designed by Chicago-based Adrian Smith + Gordon Gill Architecture. Construction of the $1.2 billion tower begins in December and is expected to take five years to complete. The tower’s height has not been revealed, but it will be the first building to be at least 3,280 feet tall. It would measure more than 560 feet taller than the world’s currently tallest building, the 2,717-foot Burj Khalifa, in Dubai, UAE. Kingdom Tower will house a hotel, apartments, condos, office space, and an observatory.