The Block of Discord on Passeig de Gràcia, Barcelona

On this stretch of less than 200 meters, there stand three houses built by the most famous architects of Barcelona at the time: Casa Lleó Morera by Lluís Domènech i Montaner, Casa Amatller by Josep Puig i Cadafalch, and Casa Batlló by Antoni Gaudí. These three architects were known as the 'Three Masters of Barcelona Architecture', and they designed nearly all the wealthy residences and iconic landmarks of the city: Park Güell, Palau de la Generalitat de Catalunya, Parc de la Ciutadella, and more.

It was a time of urban expansion in Barcelona. The old city walls were demolished, and wealthy merchants moved to the adjacent Passeig de Gràcia. To build this grand avenue, the king even increased taxes on livestock raising. With Spain losing most of its overseas colonies, merchants turned their focus inward, sparking an unprecedented industrial and economic boom. The rich traveled across Europe and brought back their aesthetic sensibilities, commissioning architects to build homes that showcased their wealth and artistic taste. Urban planners, aiming to avoid the overcrowding and disease that plagued the old city, required all new homes to have interior courtyards for ventilation.

The first house to be built was Casa Amatller, commissioned by a chocolate merchant. Visitors who buy a ticket today are still offered a cup of hot chocolate. The Amatller family ran a chocolate business for three generations. The young heir traveled across Europe to learn chocolate-making techniques and introduced innovative packaging and marketing, sparking a craze for collecting chocolate wrappers. After Mr. Amatller's death, his daughter never married; upon her passing, the foundation her father had established turned his collection of art books into a library within the house. 'Amatller' means 'almond blossom' in Catalan. Puig i Cadafalch incorporated the almond blossom motif into every decorative element of the house. The almond blossom tiles later became a hallmark of Barcelona's streets, still used on many sidewalks.

Casa Lleó Morera is not open to the public today. The ground floor, now a Loewe store, was once a club for the Chamber of Commerce and Industry. The owner's surname, Morera, means 'mulberry tree' in Spanish. Architect Lluís Domènech i Montaner wove this motif throughout the interior—tiles, stained glass, ironwork, furniture, and other details—with contributions from 40 artists.