If you didn’t already have Trondheim on your ‘must visit’ list, perhaps this discovery will change your mind. From archaeology.org: The Church that Transformed Norway.
When King Olaf Haraldsson gave up the old Viking gods to become Norway’s first Christian ruler, he fundamentally changed his society. Part of that legacy is the church he built in his capital city of Nidaros (now known as Trondheim), which was recently discovered at the construction site of a new office building. The church’s stone foundation is remarkably intact. According to Anna Petersén of the Norwegian Institute for Cultural Heritage Research, the nave, choir, entrances, and foundation of the altar are still in place. The church was dedicated to Saint Clements the patron of slaves and seafarers and a popular figure among observant Norse raiders. A series of radiocarbon dates shows that the church was built in the early eleventh century, which affirms historical descriptions. [continue, see photo of dig]