Roskilde is quite a pleasant town to the west of Copenhagen, but doesn't have the same importance today as it used to have when it was the capital of Denmark and one of its religious centres. The cathedral is not only very large, but is also the necropolis of the Danish royal family, resulting in a large number of graves and tombstones from many centuries. For a Protestant church, it is rather lavishly decorated, and is unique for its brick architecture. Don't miss the other major highlight of Roskilde, though - the great Viking Ship Museum, only 10-minute walk away. It shows several original ships from the Viking era, and you can also set sail in a rebuilt Viking ship, which is really a unique experience.