Kansai International Airport is located on an artificial island in the middle of Osaka Bay, Japan. To create the island, a 30 meter (98-foot) layer of earth was created on top of the seafloor with 21 million cubic meters of landfill. The material was excavated from three separate mountains. As of 2008, the total cost of Kansai Airport was $20 billion USD, including land reclamation that has been necessary to prevent its continued sinkage (7.1 centimeters per year as of 2008) into the bay.