Copenhagen, Denmark
I am only allowed to post one picture per blog. There's got to be another way but I haven't figured it out yet.
The Viking ship museum is really neat. Five ships had been scuttled a thousand years ago to block access to a bay. The ruins were discovered in the 1960s and then carefully excavated. They put all five ships back together with the pieces that remained. Then they also build sailing replicas but used ancient techniques and tools, no power equipment.