Captain Cook dubbed this inlet Doubtful Harbour in 1770, a name that was later changed to Doubtful Sound. It's actually a fjord with three branches, now called First Arm, Crooked Arm and Hall Arm. The breathtaking scenery you'll see as you sail it is entirely human-free. Helena Falls (about 50 meters, or 165 feet, high), at the entrance to the fjord, and the 600-meter (2,000-foot) Browne Falls are two sites of extraordinary beauty and power. Look for New Zealand fur seals and Fiordland crested penguins in the waters around you. Because of its awe-inspiring quietude, this barely inhabited area has been nicknamed the Sound of Silence.