Brisbane’s recorded history dates from 1799, when Matthew Flinders explored Moreton Bay on an expedition from Port Jackson, although the region had long been occupied by the Yugara and Turrbal aboriginal tribes. The town was conceived initially as a penal colony for British convicts sent from Sydney. Its suitability for fishing, farming, timbering, and other occupations, however, caused it to be opened to free settlement in 1838. The town became a municipality in 1859 and a consolidated metropolitan area in 1924. Population growth has continued to be among the highest of the Australian capital cities in the first two decades of the 21st century and major infrastructure including the Howard Smith Wharves, Roma Street Parklands, Queens Wharf, the Brisbane Riverwalk, the Clem Jones, Airport Link, and Legacy Way road tunnels, the Airport, Springfield, Redcliffe Peninsula and Cross River Rail lines have been completed or are under construction. Brisbane’s metropolitan area has a population of over 2.5 million and the South East Queensland metropolitan region, centred on Brisbane, encompasses a population of more than 3.6 million.