Transport in Auckland, New Zealand's largest city, is defined by factors that include the shape of the Auckland isthmus (with its harbours creating chokepoints and long distances for land transport), the suburban character of much of the urban area, a history (since World War II) of focusing investment on roading projects rather than public transport, and high car-ownership rates. Auckland has New Zealand's largest commercial port (mostly used for international commerce) and the country's largest international airport. It also has the Southern Hemisphere's largest marina.