The Castle Rock Tower lies at a high point on the Castle Rock of Tønsberg, where Norway’s finest medieval castle once stood. You can still see significant remains of Haakon Haakonsson’s castle here, which was built in the thirteenth century. The observation tower here, which stands seventeen metres high, is a superb place to take in views of the harbour and surrounding countryside, as the Rock already stands sixty metres above sea level. It was built in 1888, and carries three royal inscriptions.