The best place I've seen huge ships is Hamburg. People sit and picnic on beaches along the river in the summer, and enormous container and car carrier ships go past.
We had a team we work with a lot over here in HH and went on the treasure hunt on the Rickmer Rickmers as an event. That was very nice - they spread a bunch of little puzzle boxes across the ship so you can search for these, walk through the museum and look at stuff. And the puzzles were neat as well - you'd use the compass the actual helmsman used back in the day to figure out where east is to find some clue, count pests in cargo and such. Very recommendable and a lot of fun.
We just didn't climb up the ropes in winds that almost pushed you over on foot, haha.
