Built by Antoni Gaudí for his patron Eusebi Güell, this singular building was Gaudí’s first major work and the beginning of a long-running collaboration between the two men, which resulted in some of the most noteworthy buildings in Barcelona. Güell, who made a great fortune during the industrial revolution in the late 19th century, wanted to build a large stately mansion in the heart of Barcelona. He acquired the houses adjacent to the one he had inherited from his father near the popular Las Ramblas Boulevard, until he took over…