While the Casa Batlló shows the excessive imagination of Gaudí and the Casa Amatller is a brilliant reinterpretation of the Gothic style by Puig i Cadafalch, the third element of Barcelona’s Mansana de la Discordia (Block of Discord), Casa Lleó i Morera, represents the elegance of details. Working on the building were the forty best craftsmen of the period, following the orders of Lluís Domènech i Montaner.

In 1902, Francesca Morera commissioned the modernist architect to remodel the property she had inherited on the Eixample. When the owner died, the work was continued by her son Albert Lleó i Morera, who gave his name to the building. In fact, allusions to the family surname are repeated in the images that decorate the building throughout.

Domènech i Montaner added a floor and a tempietto on the roof. This tower, in line with the main floor balcony, simulates a non-existent symmetry in the building. Especially notable in the richly decorated façade, are the female figures by Eusebi Arnau. The most significant example are those on the first floor balconies where there are four women who carry allegorical instruments of modernity in their hands - photography, electricity, the phonograph and telephone.
Once inside the building, both the lobby and the entrance hall of the main floor are designed to impress the visitor. In the latter, the arches and doorways have spectacular carved reliefs. One of them is the story of the lullaby, La dida de l’infant rei (the Nurse of the Infant King), a tribute to the son of the owners who died as a newborn.

Much of the work of Domènech i Montaner’s team of artisans is concentrated in the two large living rooms. Notable are the stained glass windows: eight panels of mosaic and porcelain reliefs depict rural scenes with characters from the family. The furniture and dado panels that were in these rooms are preserved in the MNAC (National Art Museum of Catalonia).

The Casa Lleó i Morera, like other bourgeois properties, was a "house for rent" (the family of the owners lived on the main floor and the remaining floors were rented out). Even so, the desire was that the same exacting building standards and aesthetic quality should be maintained over all the floors.