The Galapagos Islands are a small archipelago of islands belonging to Ecuador in the eastern Pacific Ocean. The islands are quite remote and isolated, lying some 1000 km (620 miles) west of the South American continent. The Galapagos archipelago consists of 13 main islands and 6 smaller isles, which together embrace some 50,000 sq km (19,500 sq miles) of ocean. Ongoing seismic and volcanic activity reflects the processes that formed the islands. These processes, together with the extreme isolation of the islands, led to the development of unusual animal life – such as the land iguana, the giant tortoise and the many types of finch – that inspired Charles Darwin’s theory of evolution by natural selection following his visit in 1835.