With 1.6 million inhabitants in the inner city, and 5 million residing in greater Barcelona, it is the third largest city on the Mediterranean. The city layout can be described as a baseball diamond: the Mediterranean coast is from home plate to first base; the Besos river is from first to second base; the Collserola mountain range is from second to third base; and the Llobregat river flows from third base to home base. The diamond is cut in half by Avinguda Diagonal, while the densely populated neighborhoods of El Raval (known for great bars), L'Eixample'shigh-street shopping, and the medieval Barri Gotic. The city center is easily walkable, and a few metro stops will get you to the beautiful sand on Barcelona beach. 

Ciutat Vella (Old City): you will probably spend most of your time in Ciutat Vella, the compact core of Barcelona--ideal for strolling, shopping, and people-watching. The lively pedestrian area of the Ramblas winds through the heart of the Old City from Place de Catalunya to the harbor. Ciutat Vella is divided into thirds by the Ramblas, Via Laietana, and Barri Gotic. To the east of Via Laietana is the trendy El Born district (La Ribera), a shopping, dinning, and nightlife mecca centered on the Picasso Museum and the Church of Santa Maria del Mar. The Raval, west of the Ramblas, is enlivened by its university and modern-art museum, but is least visited by tourists (some parts can be dodgy and should be avoided).

Harborfront: Port Vell, the old harbor, shines with landmark monuments and new developments. The Ramblas and the modern Maremagnum shopping complex are connected with a pedestrian bridge.

Barceloneta: a traditional fishing neighborhood of gritty charm and good seafood restaurants lies on the peninsula across the quaint sailboat harbor.

Forum: a gorgeous, man-made beach several kilometers long leads to the commercial and convention district.

L'Eixample's: above Ciutat Vella, the bustling hub of Placa de Catalunya, is the elegant Eixample district, where much of Barcelona's Modernista architecture is located (especially along the Passeig de Garcia, the Quadrat d'Or. Beyond is the Gracia district and Antoni Gaudi's Park Güell.