I'm an Abba fan so I was happy that Virginia and I went to the Abba museum in Stockholm, next to a Tivoli-ish fun fair. Nostalgic and a welcome change to seeing castles and museums.
I did learn details which everyone else probably already knew about Abba and its history. I also got postcards there which I sent back home.
I still listen to music by Abba among others when I need to drown noise at work.