Whale sharks are the largest shark in the ocean. They are also the largest fish and they reach an incredible length of 20m (60 feet). Estimates of their weight place them at up to 45,000kg (100,000lbs). They are truly majestic giants of the deep. Anyone lucky enough to see one swimming in the wild will never forget the experience. These lucky scuba divers have traveled to the Galapagos Islands to swim in the water near Darwin Island, a remote area where three strong ocean currents collide. The upwelling of cold water brings nutrients and food from deep in the ocean to the surface. Animals such as Galapagos sharks, hammerheads, and stingrays congregate here. For mysterious reasons that baffle scientists, whale sharks also cruise through here during certain times of the year. They are almost exclusively large, pregnant females. It is believed that they come here to give birth, but everything about this possibility is little more than theory. The babies are almost never seen. Watching a whale shark cruise past, seemingly unconcerned with the presence of comparatively tiny humans, is simply awe-inspiring. It is a life-changing moment when it becomes clear that we, as humans, are small and clumsy in this underwater realm. The whale shark could easily increase its speed or simply dive deep, as they often do to avoid predators. They are gentle beasts with no ability to bite or defend themselves. They outswim predators when needed. This whale shark was not concerned with the divers, swimming slowly through the group. Perhaps the whale shark was equally curious about them. Either way, these divers will never forget this underwater encounter.