For millions of years, the blue-footed boobies danced and honked, the frigate birds preened, the giant tortoises lumbered about and the marine iguanas adapted to life at sea. In the remote Galapagos Islands near Ecuador, it's an animal paradise, a tropical Eden of creatures that doesn't exist anywhere else.
As we discovered during our journey to the Galapagos, it's not just that many of the creatures here are unique, it's that they have no fear of humans.
The animals are so unguarded because for millions of years they lived here in splendid isolation. But not anymore.
Call it the invasion of the tourists.
The world, it seems, wants to see this most exotic of places. But someone forgot to tell the animals. That became clear when we got off the plane at Baltra, the main airport in the Galapagos. A giant iguana was lounging in the sun on the runway. An airport worker scurried out and gingerly chased the lumbering creature out of the way taxiing airplanes.
Clearly, protecting the fragile ecosystem and managing a growing tourism industry is a balancing act.
"Nightline" joined a group of American tourists for a few days of their Galapagos voyage to see how man and nature are co-existing 600 miles off the coast of South America in the Pacific Ocean. It quickly became clear that the remoteness that shaped the islands and allowed the animals to evolve in their different ways is no longer enough to protect them.
While some tourists stay in hotels on the main islands, most opt for the tourist boats. Our boat carries a dozen passengers. Every boat, every tourist group, must have a licensed Ecuadorian guide.
Ours is Carmen Guzman. She has a Ph.D. in biology and environmental management.
"This is the place where we can get very close to the animals, and it's really one of the few places in the world where you can notice that the animals are not afraid of people," she told the eager group of tourists.
An hour later, we were aboard small inflatable zodiacs that allowed us to navigate shallow waters and the shoreline. We got our first glimpse of exotic creatures as we motored quietly into a lagoon called Black Turtle Cove, a mangrove swamp, that is a breeding ground for the Pacific green sea turtle.
As if on cue, the turtles appeared. There were quiet whispers of awe. The click of camera shutters punctured the silence.
At sunset, our zodiacs steered towards a massive mangrove tree dotted with thousands of herons, like ornaments on a Christmas tree. The white feathers of the herons reflected the pink-orange glow of the setting sun. It was a spectacular sight.
Day two took us to an island called Rabida, famous for its red sand and its abundant wildlife. As soon as we hopped off the boats, we were distracted by a baby sea lion.
These creatures exude a cuteness that borders on seduction. The tourists flocked around, snapping pictures and gasping in admiration. The sea lion and its mates seemed content be the subject of so much admiration. And as we were beginning to learn, those sea lions had a habit of stealing the show.
A walk down the beach revealed a rookery of pelicans. Dozens of them are perched in nests along the steep hillside. Tiny chicks screeched for feed, diving into a mother's pouch when she returned with fresh fish. The tourists were enthralled. The pelicans, just feet away from us, were indifferent.