Palau de la Música Catalana (Palace of Catalan Music) - Barcelona, Spain - a concert hall designed in the Catalan modernista style by the architect Lluís Domènech i Montaner - built between 1905 and 1908 for the Orfeó Català, a choral society founded in
Art Nouveau Tour of Barcelona. This is Casa Batllo, designed by Gaudi. Spain was not drawn into WW I and as such during that time, had prosperity. As as result, there are over 400 Art Nouveau structures in Barcelona.