During the winter months, the seven-mile string of beaches ringing Oahu's northern waters is most famous for its hugely popular surfing venues, including Waimea Bay, Sunset Beach, and the notorious Banzai Pipeline. If you want the thrill of seeing sharks in the wild, head to Sharks Cove on Oahu's north shore. This natural reef is home to white-tipped reef sharks-see if you can spot their fins in the water, but don't try swimming here!