The Galápagos Islands lie 600 miles off the coast of Ecuador - volcanic peaks rising from the Pacific, formed by a geological hotspot over the past 4 million years. The islands were never connected to the mainland. Every species that lives there arrived by flying, swimming, or floating on debris.

Isolation created a natural laboratory. Species that colonized the islands evolved separately from their mainland ancestors and from each other. Each island developed its own variations. The Galápagos became a living demonstration of evolution in action - though Darwin didn't fully understand this until years later.

Darwin was 26 years old when the Beagle anchored in the Galápagos. He spent five weeks exploring four islands, collecting specimens of everything: plants, insects, birds, reptiles. He was most struck by the mockingbirds, noting that each island had a slightly different type.

The finches he collected seemed unremarkable at the time. Only later, when ornithologist John Gould examined them in London, did their significance become clear: 13 distinct species, all descended from a common ancestor, each with beaks adapted to different food sources. Darwin had his evidence.

Darwin spent decades developing his theory after returning to England. The Galápagos observations were crucial: species weren't fixed creations but descendants of common ancestors, modified over generations by natural selection. Those with traits suited to their environment survived and reproduced; those without died out.

The theory was revolutionary - and dangerous. Darwin knew it would scandalize religious society. He delayed publication for 20 years, finally releasing 'On the Origin of Species' in 1859 only because Alfred Russel Wallace had independently reached similar conclusions. The Galápagos finches became evolution's most famous example.

The Galápagos remain one of Earth's most remarkable ecosystems. Giant tortoises live over a century. Marine iguanas dive for algae - the only seagoing lizards. Blue-footed boobies perform mating dances. Flightless cormorants have vestigial wings. The animals show no fear of humans - they evolved without predators.

Many species exist nowhere else on Earth. Each island has its own subspecies of tortoise, identifiable by shell shape. The finches still demonstrate evolution: during droughts, those with larger beaks survive; during wet years, smaller-beaked birds thrive. Natural selection continues, observable in real time.

The Galápagos are now a UNESCO World Heritage Site and Ecuador's most famous national park. Tourism is carefully controlled to protect the fragile ecosystems. Scientists continue studying evolution in action. Conservation efforts have saved species that nearly went extinct.

Darwin's theory of evolution became the foundation of modern biology - the framework that explains everything from antibiotic resistance to human ancestry. The Galápagos, where a young naturalist observed birds with different beaks, became the birthplace of an idea that transformed science. The islands that inspired Darwin continue inspiring visitors who walk the same shores he explored nearly 200 years ago.