If you look up La Ramblas (away from the sea), you see can a big mountain with an interesting looking church on it. That's Tibidabo. Read on for why it's worth the hike up there.
Before you even get up to Tibidabo, check out CosmoCaixa, one of Europe's best science museum, which can be found near the Avinguda de Tibidabo metro station. Cosmocaixa is a state-of-the-art interactive museum with exhibits for all ages (including three rooms just for children under ten).
2. Ride the Blue Tram
We're still not on Tibidabo yet, but there's more fun to be had on the way. The blue tram runs (weekends only, at least out of season) from the Avinguda de Tibidabo metro station up to the look-out point and funicular station on Tibidabo itself.
3. Enjoy the Views from Mirablau
After you get off the blue tram, stop for something to drink at the Mirablau cafe, which has great views over the city. The service here isn't great, but that's not why you come here.
4. Tibidabo's Funicular
We've still not gone all the way yet, but here we have another fun form of transport to enjoy the children. Note that the funicular stops quite early (about 4pm out of season), so get there early.
5. Tibidabo Amusement Park
Tibidabo's amusement park is the oldest in Spain and it still has many of its original rides, along with more hair-raising ones for modern people.
6. Tibidabo Automaton Museum
Near the amusement park is the Tibidabo Automaton Museum, an exhibition of classic clockwork figurines.
7. Sagrat Cor Church
The Sagrat Cor (Sacred Heart) church (that's the building you can see on Tibidabo from all over the city) is an impressive modernist/neogothic church near the amusement park.
8. Collserola Tower
You may think you have a great view from the Amusement Park, but if you climb to the observation platform on Collserola tower you'll have an even better one!
Take a walk or hire and bike and explore the beautiful Collserola Park on two weeks instead. This is an especially beautiful place to be at sunset.
10. Enjoy the Architecture
There is a number of interesting buildings on or around Tibidabo. On the mountain itself is Fabra Observatory, one of the oldest still-functioning planetariums in the world. Back at the metro station is La Rotonda, a former hotel (it's now a hospital) built in Barcelona's characteristic modernist style .