Kobe Airport
The island had been predicted to sink by the most optimistic estimate as the weight of the material used for construction compressed the seabed silts. However, by 1999, the island had sunk – much more than predicted. The project became the most expensive civil works project in modern history after twenty years of planning, three years of construction and US$15bn of investment. Much of what was learned went into the successful artificial islands in silt deposits for New Kitakyushu Airport, Kobe Airport, and Chūbu Centrair International Airport. The lessons of Kansai Airport were also applied in the construction of Hong Kong International Airport.