Honeymoon ideas for a nerdy couple

When looking for honeymoon destination ideas online you get almost entirely tropical places with nice beaches and resorts, etc. But my fiancée and I are not outdoorsy people. You're more likely to find us spending all day at a museum than at a beach. We'll do some outdoors stuff for sure, but it's important that we have stuff other than that to do. My financee is also from Europe, so I'm trying up avoid popular European destinations (with the exception of maybe Spain). Anyone have any ideas?