Based on queries that are constantly repeated I have decided to provide a list of links to some key sites:

Transport in Barcelona

TMB – Metro and Bus (T-10 ticket will give you 10 rides for 10 euros) – and Metro Map

Renfe Cercanias (Greater metropolitan area and beyond) – buy 10 ride multizone tickets to save

Ferrocarrils (including line to Montserrat) – Same multizone ticketing applies

Aerobus

Taxis – there are many different taxi companies, but the charges are set by meter (standard)

Taxi Applications – Hailo and Cabify – alternative taxi service

Museums – Hours and locations

Picasso Museum

Miro Foundation

MacBa –Contemporary Art Museum Barcelona

MNAC – Museu Nacional Art Catalunya

Monasteri de Pedrables

Maritime Museum

Caixa Forum

 

Buildings to Visit

Modernist architecture and buildings

Gaudi – Park Guell, Palau Guell, La Pedrera, Casa Batllo, La Sagrada Familia, Casa Vicens

Domenech i Montaner – Palau de la Musica, Recinte Hospital Sant Pau

Puig i Cadafalch – Casa de les Punxes, Casa Amatller

Modernisme Museum