Lisbon’s newest area is the Parque das Nações (Nations’ Park), which was built along the estuary of the Tejo river in 1998 for the Expo ’98. This was a significant year for Portugal, as it celebrated the 500th anniversary of Vasco da Gama’s discovery of India in 1498 and two of the major structures built at this time were named after the great voyager. The Torre Vasco da Gama (Vasco da Gama Tower) on the Cais das Naus, standing at 145 metres, is Lisbon’s tallest building. Built on the site of a former oil refinery, it is designed to looked like the sail of a caravel (the type of ship sailed by Vasco da Gama). It originally had a public restaurant and observation deck at the top of the tower, but it is now part of the luxury Myriad Hotel and no longer open to the public. The Ponte Vasco da Gama (Vasco da Gama Bridge) which goes across the Tejo river from the suburb of Sacavém on the north bank to the suburbs of Montijo and Alcochete on the south bank, is 17 kilometres in length and is the longest bridge in Europe.