Dusky Sound lies among the grand fjords of Fiordland National Park in the southwest part of New Zealand's South Island. Named by Captain Cook when he sailed by at dusk on his first voyage in 1770, this spot holds one of the area's largest fjords, at almost 25 miles long. During the rainy season, you can spot hundreds of waterfalls splashing down from the verdant green hills into the dark deep waters. During your Dusky Sound cruise, keep an eye out for sunbathing seals in repose on Seal Rock. Look out for Astronomer's Point, a former observatory dating back to 1773 that overlooks the dramatic fjord.