What makes the Galápagos Islands special?

Imagine you're standing on a volcanic island in the middle of the Pacific Ocean, a thousand kilometers from anywhere. The rocks are black and jagged. A penguin waddles past — wait, a penguin? You're practically on the equator. What is going on here?
The Galápagos Islands are special because they're ridiculously isolated. They sit alone in the ocean, far from any continent. For millions of years, only the toughest travelers could reach them: birds blown off course by storms, seeds floating on driftwood, maybe a lizard clinging to a log. Once something arrived, it was stuck — and it had to figure out how to survive.
