Gliding through the peaceful waters of the Limfjord in northern Denmark, you’ll see green valleys, picturesque islands and harbors and dramatic coastal cliffs. The Limfjord, a shallow part of the North Sea, is considered a fjord in the Norwegian sense of the word (\"fjord\" can refer to a wide range of waterways). It is not technically a fjord in the geological sense, though, because it has inlets from both the North Sea and Kattegat and separates North Jutlandic Island from the rest of the Jutland Peninsula. The main port of the Limfjord is Ålborg, where a railway bridge crosses the fjord. There are several other ports, bridges and ferry crossings along the 110-mile-long body of waters. The most notable island is Fur. Located off the northern tip of the Salling Peninsula and one of the region’s geological gems, it has fewer than 1,000 inhabitants and is linked to the mainland by a 24-hour ferry. The island’s most unusual resource is its deposits of diatomite, used to make cat litter. Fossil-hunting is a popular pastime here: Millions of years ago turtles, birds and other small animals were trapped in the island’s volcanic ash.