Japan has more than 300 high-rise buildings above 150 m (490 ft).[1] Unlike other Asian countries with skyscrapers exceeding 400 m (1,300 ft) in height, Japan's skyscrapers are relatively shorter. Construction is difficult due to the high cost of labour and construction material, as well as legal height restrictions (as in many other developed countries, particularly due to the proximity of Haneda Airport); all buildings above 50 m (160 ft) must also be as earthquake-proof as possible and adhere to other strict structural standards.