Best city breaks with kids

[gold22]

I'm just looking for recommendations for city breaks abroad which would be fun for both adults and a 6yr old. He's pretty good in the sense he likes new places and is quite mature for his age, but he's still a 6yr old so I'd like to incorporate some things for him to do too.

Loads and loads for kids in Barcelona - aquarium, zoo, cable car, fun fair, funky buildings, magic fountains, etc

I was going to say Barcelona!
Amsterdam is good too - pancake boat, Nemo, Artis, This Is Holland, A’dam Lookout, Blue boat kids cruise

Lisbon. Great Castle, fun funiculars, fantastic aquarium and a great climb up Jesus.