Kingdom Holding Company (KHC) has revealed that work is to start on the world's tallest building - Kingdom Tower in Jeddah, Saudi Arabia - following the signing of contracts.

Chicago, US-based Adrian Smith + Gordon Gill Architecture (ASGG) are behind designs for the new building, which will stand more than 1,000m (3,281ft) above the city. Located at the heart of the wider Kingdom City development, the tower will be at least 173m (568ft) taller than Dubai's Burj Khalifa and will feature a Four Seasons hotel.

One of the world's highest observatories and Four Seasons serviced apartments will also be included as part of the complex, along with office space and luxury condominiums.

ASGG - working with Environmental Systems Design and Thornton Tomasetti - has been selected for the project following an international design process. The team is also behind the masterplan for the Kingdom Tower Waterfront District around the proposed tower, which will comprise two hotels; a shopping mall; and open spaces.

HOK Architects are behind the wider Kingdom City vision. Image: (c) Adrian Smith + Gordon Gill Architecture