Roskilde is famous for the viking ships they recovered from the fjord. Roskilde use to be the capital of Denmark and was a very large viking trading port. The sunk ships in the fjord to protect the harbor from invasions.
Besides the long ship. There are also other smaller viking age ships that were built in the harbor, thanks to the viking ship museum. There are also some other period ships in the harbor also. They seem to keep the elements of the viking ships