The Republic of Cape Verde ⁱ/ˌkeɪp ˈvɜrd/ (Portuguese: Cabo Verde, pronounced: [ˈkabu ˈveɾdɨ]) is an island country, spanning an archipelago of 10 islands located in the central Atlantic Ocean, 570 kilometres off the coast of Western Africa. The islands, covering a combined area of slightly over 4,000 square kilometres (1,500 sq mi), are of volcanic origin and while three of them (Sal, Boa Vista and Maio) are fairly flat, sandy and dry, the remaining ones are generally rockier and have more vegetation. However, because of the infrequent occurrence of rainfall the overall landscape is not particularly green, despite what the country's name suggests (verde is Portuguese for "green"). The name of the country stems instead from the nearby Cap Vert, on the Senegalese coast, which in its turn was originally named "Cabo Verde" when it was sighted by Portuguese explorers in 1444, a few years before the islands were discovered.