The Amsterdam Arena is an innovatively constructed stadium in the Netherlands, considered as the largest stadium in its city. Its construction started in 1993 and ended in 1996 with a cost of €140 million. A Dutch architecture Rob Schuurman designed the stadium with a capacity of 53,490 spectators that can be extended to 68,000 for music concerts. The Amsterdam Arena is currently home to the Ajax Football Club. It has also been the stamping ground for the Amsterdam Admirals (a professional American football league team), from 1997 to 2007. The stadium boasts of a retractable roof that covers a grass surface. Four different roofs in a year were tested before finalizing one. The arena is used to host various sports and entertainment events and has a parking facility for 500 cars inside it and for 12,000 cars outside.