The building is the tallest in Saudi Arabia, and was topped out in January 2001.

Kingdom Centre was planned from the beginning as an iconic symbol of Saudi Arabia, and the final design was selected after a 3-year process which included over 100 submissions by major architectural firms.

The tower's unique shape culminates in a triangular opening spanned by a 56 meter skybridge with a public observation deck.

Occupants include a five-star hotel, a major bank headquarters, a sports club, a wedding and conference center, and a luxury condominium and apartment complex.

Kingdom Centre is the tallest skyscraper in the world below 50 floors.

At its completion this was the 25th tallest building in the world, and the tallest of the 21st century.

The spaces to the left and right of the hole contain an enormous latticework of diagonal steel beams. On the restaurant level there is a conference room with a skylight looking up at this area.

The hotel's ballroom is the largest in Riyadh, and the largest in the entire Four Seasons hotel chain.

The observation deck has a steeply arched floor, and features diagonal cross-beams along the windows.

The building has an entrance on each of its four sides, each one serving a different usage (hotel, shopping, ballroom, and apartments/offices).

The tower is aligned in a direct axis with Al Faisaliyah Center, Riyadh's other major skyscraper.

A three-level shopping center fills the east wing. The mall won a major design award.

Landscaped courtyards filled with palm trees welcome visitors on the north and south sides of the tower.

The lighting fixtures in the driveway mimic the shape of the tower, with a recessed arc in place of the hole.

The inverted catenary arch at the top was described by the developer as a "necklace" for the city of Riyadh.

The large opening is illuminated at night in continuously changing colors.

Almost all of the facade is reflective blue glass, but the opening is lined with aluminum to highlight the unique shape.

The ellipse motif taken from the tower's footprint appears also in the light fixtures, ceiling panels, entrance canopy, wastebaskets, and furniture.

The main lobby is a soaring elliptical space with ribbed vaulting, elevated walkways, a fountain, and rows of palm trees.

Kingdom Centre is the winner of the 2002 Emporis Skyscraper Award, selected as the "best new skyscraper of the year for design and functionality".

Hear the radio interview (21MB, MP3) about the Kingdom Centre held by the BBC with Daniel Kieckhefer, Emporis senior editor from Chicago.