Parc Montjuïc is the hill in the southwest of Barcelona and allows great views of the city and the Mediterranean. In or near the vast park, you will find the Fundacio Juan Miro, the national museum of art, beautiful colour foutains, a castle and amazing botanical gardens. The botanical gardens include the National botanical garden, the Laribal garden, the fortress and the desert gardens of Mossen Costa i Llobera. The gardens are all unique and distinctive with a variety of plants species being represented. Some of the gardens are more formal with terraced and boxed-in garden rooms like the Laribal gardens. While other gardens like the National botanical gardens are more relaxed and park-like with indigenous plantings of the region and countryside. There are also exotic gardens like the Mossen Costa i Llobera, which has an impressive collection of desert, cactus and sub-tropical plantings amassed into one of the largest cactus and succulent collections in the world.
You will find great information on the parc here.
There are different ways of getting there:
1. Teleferico de Barcelona: From Port Vell (found close to the end of Las Ramblas) you can hop on a cable car for a scenic cruise across the Mediterranean sea that will land you around halfway up the mountain... All for a hefty €11.00 one way or €16.50 return.
2. Metro: At Parallel Metro station take the Funicular. You can use a public transport ticket, so it's a cheaper option and works out at €1.03 one way or €2.06 return with a T10 ticket. That said, it only takes you halfway up, but handy if you're travelling from the other side of the city.
3. Bus: The cheapest choice is getting the 150 bus from Plaza Espanya, which will drop you off right outside the castle. Again, €1.03 one way or €2.06 return with a T10 ticket.