This stunning building on Passeig de Gracia is Casa Amatller. Built in the Modernisme style and designed by Josep Puig i Cadafalch, one of the great Catalan architects at the beginning of the 20th century. It is just next door to Casa Batllo, of which you can see a small part in the upper right corner. You can see much more of it here.
Gaudi’s genius. Beauty that goes well into details. Here are some from Casa Batllo, on Passeig de Gracia.