The Spinnaker Tower (previously known for sponsorship reasons as the Emirates Spinnaker Tower) is a landmark observation tower in Portsmouth, England. It is the centrepiece of the redevelopment of Portsmouth Harbour, which was supported by a National Lottery grant. Its shape was chosen by Portsmouth residents from a selection. The tower, designed by local firm HGP Architects and engineering consultants Scott Wilson and built by Mowlem, reflects Portsmouth's maritime history through its being modelled and named after a spinnaker, a type of sail that balloons outward. The tower was opened on 18 October 2005.