Las Ramblas in Barcelona is approximately 1.2 kilometres long with Port Vell (near the cruise port terminal) at the Southern most end and Plaça Catalunya at the northern most end.
If you have your back to Port Vell and you are looking up towards Catalunya along the Ramblas on your left hand side is the Raval area and on your right-hand side is the Barri Gotic (or Gothic Quarter).
Barcelona Las Ramblas can also be roughly divided into seedy and non-seedy areas. This distinction between seedy and non-seedy becomes a lot clearer during the night time when the Southern most end of the Ramblas becomes something of a red light district and is frequented by night women (prostitutes).
La Rambla is primarily pedestrianised with only two narrow one-way traffic roads which run on either side of the central Ramblas Boulevard.
Barcelona city council have restricted traffic flow through this region and you have the overwhelming feeling that pedestrians rule in this area (which makes a welcome change). Unlike other cities that have huge roads running through the middle Barcelona has chosen to structure the road system such that the heart of the city centre is primarily pedestrianised with larger roads that service the periphery.