The urban area of São Paulo has a population of 36.8 million people. When Pedro Álvares Cabra of Portugal came to Brazil in 1500, the population of Portugal would have been about 1-1.2 million. Estimates for the indigenous population of South America before the arrival of Europeans range from 50 to 100 million. São Paulo remained a poor region until the discovery of Gold in the 1690s. The town then became a centre for explorers looking to venture inland to seek fortunes. Trade grew around providing accommodation and food for missionaries, traders and adventure seekers. After the gold ran out, focus shifted to sugar and later coffee. When Brazil became independent from Portugal in 1822, São Paulo was named an imperial city. Today, it is the biggest city in the southern hemisphere.