Casa Batlló is in the very heart of Barcelona in Passeig de Gràcia and for sure this place should be a part of your Barcelona day tour. Its hogged roof which looks like a dragon's back, mosaic frontage which colour depends on lighting, and balconies which look like big-eyed heads of flies make indelible impression on every tourist.
I visited Barcelona in October and the queue to Casa Batlló was about 100 meters at day time and in the evening at about 8 o'clock it took me about 10 minutes to get in.
Casa Batlló is open from 9 a.m. to 9 p.m. You cannot enter it after 8 p.m.
Entrance ticket costs a little more than € 20. The price includes audio guide which will be given to you even if you don't want to have it.
The excursion lasts about an hour and embraces several floors, open veranda, stairs, and patio. Interiors are amazing and very unusual.
In summer night concerts are held in Casa Batlló and tourists have a chance to see in unusual atmosphere.