This castle at the mouth of the fjord was probably built by Valdemar the Great in the 12C and has been frequently modified. Its history museum includes a section on the 1864 war against Prussia, as a result of which the Danes lost South Jutland. The collections are on three floors. Queen Dorothy's Renaissance chapel (ground floor) houses a fine triptych and marble and alabaster baptismal fonts. The great ballroom on the second floor of the North Wing boasts a parapet and medieval machicolations.