Take the FGC train to Avinguda del Tibidado then bus 196 to this incredible science museum. €6 for adults, kids under 16 free. The Amazon rainforest section is a real indoor jungle with live animals, waterfalls, and climate control.

The hands-on physics exhibits actually work (unlike most science museums) and there's a proper cafeteria with reasonably priced food. Plan minimum 3 hours but could easily do 5-6 with curious kids.

Stroller accessible throughout. They have family restrooms and a quiet nursing area on the second floor.