The region is also home to the largest airport in Croatia—the Zagreb Airport. In April 2012, a 30-year concession contract to develop and manage the airport as a regional transport centre was signed by the Government of Croatia and Zagreb Airport International Company Limited. The only navigable river in the region is the Sava, downstream of Sisak. The navigable route became disused after onset of the Croatian War of Independence in 1991, and it has not been fully restored since the end of the war, limiting the size of vessels that may reach Sisak.