The Casa Batlló, an Art Nouveau 19th century building, is an apartment building in Barcelona. It was built by Antoni Gaudí (1852-1926) and Josep Maria Jujol (1879-1949) in the year 1877 and remodelled in the years 1905–1907. The facade of the Casa Batlló is made of sandstone covered with colourful trencadis and straight lines are avoided. The ground floor, in particular, is rather astonishing with tracery, irregular oval windows and flowing sculpted stone work. The roof is arched and was likened to the back of a dragon. The house can be visit by the public.