Having seen a lot of cathedrals in the process of visiting World Heritage Sites, it takes something a little different to linger in my memory. Roskilde certainly does that. As Els points out it is a Protestant cathedral, and this means that it has a slightly austere brick and whitewash interior. This was actually very impressive and helped to focus attention on the other artistic details, and I guess for parishioners there it helps them focus on their worship. I really enjoyed studying the intense detail of the carved altar piece and choir stalls, which were elegantly lit and open to allow close inspection.
The main thing that impressed me though was the side chapels with the tombs of Danish royalty. This was a big surprise to me as this type of monument normally leaves me indifferent. They were very elegant, and the use of space within the chapels was very restrained. At no stage was I overwhelmed by what I was seeing, this allowed my focus to remain on the works of art. This may not be the most impressive looking cathedral interior on the list, but actually that is its main advantage.
I almost missed seeing the interior, but I am very glad that I made time for the short hop out from Copenhagen to get inside. The exterior of the cathedral is nice but not particularly remarkable, but the real highlight is the restrained yet outstanding interior.
Roskilde is a little different to the other European Cathedrals on the list and well worth a trip to see.