The Galápagos Islands are a chain of islands, or archipelago, in the eastern Pacific Ocean. They are part of the country of Ecuador, in South America. The Galápagos lie about 966 kilometers (600 miles) off of the Ecuadorian coast.

There are thirteen major islands and a handful of smaller islands that make up the Galápagos archipelago. The largest of the islands is called Isabela. It is approximately 129 kilometers (80 miles) long. Repeated volcanic eruptions helped to form the rugged mountain landscape of the Galápagos Islands.

The Galápagos are best known for their diverse array of plant and animal species. Many species are endemic, which means they are not found anywhere else in the world. These include the giant Galápagos tortoise (Chelonoidis nigra), the marine iguana (Amblyrhynchus cristatus), the flightless cormorant (Phalacrocoraz harrisi), and the Galápagos penguin. The Galápagos penguin (Spheniscus mendiculus) is the only penguin species to live in the Northern Hemisphere.

Environmental conditions make the Galápagos a unique island ecosystem. The Galápagos Islands are located near the equator, yet they receive cool ocean currents. This makes for a strange mix of tropical and temperate climates. For most of their history, the islands have been extremely isolated. This combination of factors created a laboratory for the evolution of an unusual mix of plant and animal species.

Scientists have studied this complex ecosystem for more than 180 years. British naturalist Charles Darwin may be the most influential scientist to have visited the Galápagos Islands. Darwin first came to the Galápagos in 1835, on a ship called the HMS Beagle. His observations of wildlife on the island inspired his theory of evolution by natural selection.

Today, scientists study the archipelago’s aquatic ecosystems as well. For example, marine ecologist Salome Ursula Burglass works to identify and describe the plant and animal species living on and around the underwater, deep-sea volcanoes, or seamounts, in the Galápagos.