The capital city of Arizona, US will be receiving a new addition to its skyline in the form of a 430ft (131m) high Phoenix Tower.

Developer Novawest LLC and Danish architecture firm Bjark Ingels Group (BIG) unveiled plans for the observation tower, which will be located in downtown Phoenix on the Science and Technology campus.

The principle feature of the tower - which will have a total floor space of 70,000 sq ft (6,503sq m) - is a large spiralling sphere at the top that stands as a metaphorical representation of a pin.

Occupying the upper third of the Tower's structure, the observation area features views of the City of Phoenix from a singular perspective.

Visitors will have the option to travel up a wide spiral walk-way to the top of the tower - a 25ft in diameter observation deck that offers 360 degree views of the City's skyline.

The 10,000sq ft (929sq m) base of the tower will serve as a public plaza offering shade, water features and retail together with a subterranean queuing area.

The base of the observation area will also house an enclosed exhibit area featuring entertainment and educational displays and artifacts relating to the Southwest and Arizona region.

Potential themes for the exhibits are Native American history and culture, animal and plant species unique to the Arizona area or feature films and television recorded in the Phoenix area.

The tower will operate using sustainable energy practices, incorporating a blend of solar and other technologies.

A 200-seat steak and seafood restaurant and a100-seat bar lounge will also feature occupying two levels of the tower.