The city-state of Singapore has over 4,300 completed high-rises, the majority of which are located in the Downtown Core. In the city, there are 49 skyscrapers that rise higher than 140 metres (459 ft). Three buildings share the title of tallest building in Singapore: United Overseas Bank Plaza One, Republic Plaza and Overseas Union Bank Centre. The three towers, which share the title of 70th-tallest building in the world, are each 280 m (919 ft) tall. There is a height restriction of 280 metres (919 ft) for structures in the central business district of Singapore because of the proximity of Singapore Changi Airport.