Adelaide is the capital and most populous city of the Australian state of South Australia, and is the fifth largest city in Australia, with a population of over 1.1 million. It is a coastal city beside the Southern Ocean, and is situated on the Adelaide Plains, north of the Fleurieu Peninsula, between the Gulf St Vincent and the low-lying Mount Lofty Ranges. It is a roughly linear city: it is 20 km from the coast to the foothills, but it stretches 90 km from Gawler at its northern extent to Aldinga in the south. Named in honour of Queen Adelaide, the consort of King William IV, the city was founded in 1836 as the planned capital for the only freely-settled British province in Australia. Colonel William Light, one of Adelaide's founding fathers, designed the city and chose its location close to the River Torrens. Inspired by William Penn and the garden city movement, Light's design set out Adelaide in a grid layout, interspaced by wide boulevards and large public squares, and entirely surrounded by parkland. Early Adelaide was shaped by religious freedom and a commitment to political progressivism and civil liberties, which led to world-first reforms. Adelaidean society remained largely puritan up until the 1970s, when a set of social reforms under the premiership of Don Dunstan resulted in a cultural revival. Today Adelaide is known for its many festivals as well as for its wine, arts and sports revelry.