Where the lights come from is the national museum of art in Catalunya. Its an impressive building with great exhibitions and a huge collection of hostoric art. In that area you will also find Mies Van Der Roes house and Caixa forum (Av. Francesc Ferrer i Guàrdia, 6-8).
This nearly 200-year-old bar— reputedly the oldest in Barcelona, is an absynthe bar. Was one of the locations from Vicky Christina Barcelona's film.
The Marsella is one of those places that Hemingway supposedly loved to frequent (Hemingway being to bars in Spain what George Washington is to inns in New England).