A fine example of Dutch Renaissance architecture, the castle of Christian IV is truly grandiose. Built out of red-brick and embellished with stoneware decors and elegant gables, it was a royal residence for 100 years. An impressive barbican fronts the castle and a beautiful so-called Neptune fountain graces the courtyard. In 1878 it became the National Danish History Museum, home to furniture, historical objects and a fine collection of paintings.