Colònia Güell, accessible by train from Barcelona, with a multilingual audio guide

The Gaudí crypt in the Colònia Güell, with the train journey from Barcelona sorted. Taking the train significantly changes the plan: you don't need to rent a car or rely on a bus schedule, and the journey from the city is short. The colony was built in the 19th century to house the workers of a textile factory, and inside is the church that Gaudí left unfinished: only the crypt was built, which is listed as a UNESCO World Heritage Site. The audio guide is available in several languages and tells the story of the site and what Gaudí experimented with here. A note about the reservation: this ticket is non-refundable.