The Galapagos Islands were formed by volcanos about 5 million years ago, which is quite recently as compared to geologic time. Being set apart from the mainland, the Galapagos Islands developed species unique to the islands, with features not seen anywhere else in the world.
The Galapagos Islands were first explored by the Spanish in 1535. The name "Galapagos" came from the word for saddle, as this is what the explorers thought of when they saw the unique Galapagos Tortoises inhabiting the island. Equador took possesion of the archipelago located 600 miles off its coast in 1832. In 1835, Charles Darwin spent 6 weeks studying the animals of the islands, and his work here greatly influenced his "Theory of the Origin of the Species".
The Galapagos Islands consist of 13 major islands, 5 of which are inhabited today. The island of Baltra is where you would find the airport, with flights coming in from Equador. The other populated islands - Santa Cruz, San Cristobol, Isabela and Floreana - along with Baltra - have a total population of about 18,000.