A favourite outing is to take the train from St Cugat 4 stops (about 7 mins) towards Barcelona to Baixador de Vallvidrera in the Sarrià-Sant Gervasi district. Here you literally get straight out of the train and into the woods with numerous routes to explore.
Recommended by Rachael West
Contact Details: www.parcnaturalcollserola.cat
You can make the walks as long or short as you like. Taking the train is definitely part of the fun for children. Recommended for children of waking age (18 months up is fine). (Rachael West)