"Winding along the mountain that forms one edge of Barcelona, the other edge being the Mediterranean, the Carretera de les Aigües is a six-mile-long footpath where many locals go for their daily jog or weekend mountain bike ride. A long walk here comes with the added bonus of sweeping Barcelona views. The path doesn’t change in elevation, but you can branch off onto higher trails and work your way up to the top of Tibidabo at 1,680 feet. You can access Carretera de les Aigües from several spots in the upscale neighborhoods of Sarrià, Sant Gervasi, and Pedralbes, which are also home to many of the city’s schools and universities.Collserola National Park — The Carretera de las Aigües is a small part of a much larger national park, which covers the Tibidabo mountaintop and reaches down along its backside to the town of Sant Cugat. It has miles of trails for hiking and mountain biking. You can also visit the Fabra Astronomical Observatory by day for three euros or plan to visit on a weekend night for 15 euros on Fridays and 25 euros on Saturdays. Pack flashlights with fresh batteries for the night hike to get there." - MATADOR_NETWORK