The discovery of gold in Victoria in 1851 led to the Victorian gold rush and Melbourne, which served as the major port and provided most services for the region, experienced rapid growth. Within months, the city's population had increased by nearly three-quarters, from 25,000 to 40,000 inhabitants.
Thereafter, growth was exponential and by 1865, Melbourne had overtaken Sydney as Australia's most populous city.An influx of interstate and overseas migrants, particularly Irish, German and Chinese, saw the development of slums including a temporary "tent city" established on the southern banks of the Yarra. Chinese migrants founded a Chinatown (http://en.wikipedia.org/wiki/Chinatown,_Melbourne) in 1851, which remains the longest continuous Chinese settlement in the Western World.