Updated 15 November 2014
The second largest city in Spain, Barcelona is one of the most visted cities in Europe attracting millions of tourists every year.
Barcelona itself is home to around 1.5million people, with about 5million in the greater metropolitan area. It is another Olympic host city, having brought the games to Spain in 1992. Transport in Barcelona is overseen by Autoritat del Transport Metropolità (ATM).
Barcelona's metro system first opened in the 1920s. Recent years have seen considerable expansion of the system.
At street level, the network is operated mainly with buses. The Metro system and most of the bus services are operated by Transports Metropolitans de Barcelona (TMB).
All of those I saw had three sets of doors.
A number of core high frequency services are now identified by their direction of travel. Route numbers beginning with an 'H' are 'horizontal' (if you look at a map). Routes with a 'D' are 'diagonal', while those with a 'V' are 'vertical.
Some of the buses used on these core services carry a revised livery, which includes a representation of a street map.
Barcelona now claims to have the most environmentally-friendly bus fleet in Europe, with all TMB vehicles complying to at least Euro4 emissions standards.
As well as conventional diesel-powered buses, the TMB fleet also includes hybrid and gas-powered vehicles. Gas-powered buses make up around 40% of the fleet.
A considerable number of articuated buses also ply the streets of Barcelona.
Bus route 165 is unusual, in that it operates as an express service. It links Barcelona with El Prat de Llobregat.
The articulated vehicles are no longer the largest buses to be found in Barcelona. In 2013, TMB introduced three bi-articulated hybrid buses to route H12, operating as a trial alongside articulated vehicles. The bi-articulated vehicles only operate at certain times. I only just managed to track one of them down.
At the opposite end of the scale, midibuses and minibuses can also be found in Barcelona.
The red livery of TMB is not the only one to be seen in Barcelona. Buses on certain routes into the suburbs carry yellow or orange colours.
Coach services operted by Mon-Bus link Barcelona with nearby towns.
A dedicated coach service, Aerobús, runs frequently from Barcelona city centre to its airport. Long, three-axle vehicles are used.
Route A1 runs to Terminal 1, route A2 to Terminal 2. Special fares apply, TMB tickets are not valid on the Aerobús service.
Although the dedicated Aerobús services are aimed at providing the link to the ariport, a normal TMB bus service also operates. Bus route 46 runs to the airport from Plaça Espanya.
Two operators provide tours - Barcelona Bus Turístic vehicles carry a red and white livery, while Barcelona City Tour vehicles are red.
Trams disappeared from Barcelona's streets in 1971 with the exception of one line, the Tramvia Blau. This has been retained as a heritage line, providing a link between the suburban rail system and one of Barcelona's three funicular railways on the hills which overlook the city. Special fares are charged on Tramvia Blau.
Two new tram systems opened in Barcelona in 2004. Each comprises three lines, and both systems are operated by TRAM under a concession agreement. The two systems are not physically connected although there are proposals to join them.
In addition to the bus, tram and metro networks and its funiculars, Barcelona is also home to not just one but two cable car systems.
The Teleférico de Barcelona, dating from 1931, crosses the harbour.
Two cabins operate on a 1.3km route from Miramar, on the waterfront, to the side of Montjuïc which overlooks the city.
A separate cable car system operates on Montjuïc itself. The Telefèric de Montjuïc opened in 1970, although the cabins now operating date from 2007.
Both cable car systems operate as tourist attractions.
One system which is not aimed at tourists is the cycle hire scheme, Viu BiCiNg. An annual membership fee is payable to use the service, which is intended only for residents of Spain.
The reason why Viu BiCiNg is not aimed at tourists is because of opposition from commercial bicycle rental companies, which already catered for tourists before the public cycle hire scheme had been introduced.
With thanks to Richard Turner for providing a number of the images in this article.