Why this gets overlooked
Gaudí's fame is so dominant that "Modernisme" and "Gaudí" get used almost interchangeably by visitors — which skips two architects who were his genuine contemporaries and, in their own time, arguably his professional equals in reputation. Seeing their work fills out what Modernisme actually was: a movement, not a single genius working alone.
Lluís Domènech i Montaner
His masterpiece, the Palau de la Música Catalana, is arguably the single most spectacular Modernisme interior in Barcelona — a concert hall with a stained-glass skylight and ceiling that floods the space with color, structurally daring for its time. Consistently less crowded than Gaudí's sites despite being, by many visitors' accounts, just as impressive. He also designed the Hospital de Sant Pau, a sprawling Modernisme hospital complex reimagined as pavilions rather than a single block — since repurposed and open to visit.
Josep Puig i Cadafalch
Puig i Cadafalch designed Casa Amatller, sitting directly next to Casa Batlló on Passeig de Gràcia's famous "Block of Discord" — three Modernisme buildings by three different architects side by side, a genuine architectural face-off from the era. His style leans more Gothic-revival and Northern European in influence than Gaudí's organic curves, a useful visual contrast when seen back to back.
The "Block of Discord"
Casa Batlló (Gaudí), Casa Amatller (Puig i Cadafalch), and Casa Lleó Morera (Domènech i Montaner) sit on the same short stretch of Passeig de Gràcia — the nickname refers to their strikingly different, competing styles. Walking this one block is the fastest way to understand Modernisme as a movement rather than a single architect's signature.