Quelimane is a seaport in Mozambique. It is the administrative capital of the Zambezia Province and the province's largest city, and stands 25 km from the mouth of the Rio dos Bons Sinais. The river was named when Vasco da Gama, on his way to India, reached it and saw "good signs" that he was on the right path. The town was the end point of David Livingstone's west-to-east crossing of south-central Africa in 1856. Portuguese is the official language of Mozambique, and many residents of the areas surrounding Quelimane speak Portuguese. The most common local language is Chuabo. Quelimane, along with much of Zambezia Province, is extremely prone to floods during Mozambique's rainy season. The most recent bout of severe flooding took place in January 2007.