The stunning Palau de la Música Catalana is celebrating its 100th anniversary.

As the lines outside the Sagrada Famila, Gaudi's Casa Batlló, or the Palau de la Música Catalana attest, Barcelona's modernist heritage is big business.

A 50-minute tour of the Palau, which this year celebrates its centenary, costs EUR 10.

The auditorium receives around 1,200 visitors a day, divided up into groups of 50, meaning that it makes more money from tours than it does from concerts, of which it staged 359 last year.

Gaudi's elaborate work might be better known, but the Palau is the jewel in the city's crown, and is rightly regarded so by fans of early 20th-century architecture, and the peculiar style of modernism that briefly flourished in Barcelona before World War I.

It is also one of the cultural cornerstones of Catalan nationalism. In the same way that Barcelona FC's Camp Nou is much more than just a soccer stadium, the Palau is not just a concert hall.

It was inaugurated on 9 February 1908, having taken just three years to build, from a design by architect Lluís Doménech I Montaner. The Palau was an act of faith at a time of political turmoil, supposedly bringing together a cultured working class with an arts-patronizing bourgeoisie.

But for the generation that followed, the Palau's ornate interior decoration was the embodiment of bad taste, and it wasn't until the 1950s, and the emergence of a new generation, that its true worth was fully appreciated.

"The Palau's ending is a happy one, because the building wasn't demolished," says Óscar Tusquets, who has supervised restoration work over the last 20 years. "My parents' generation hated modernism. And even I was afraid of it when I was a kid," he says.

Tusquets says that Doménech faced innumerable challenges when designing the building. "Because of the shape of the plot, and the lay of the land, he had to construct the hall six meters above the ground."

To make matters worse, Doménech was asked to squeeze more seats in than had originally been planned, so he had to build a second tier above the foyer. As a result, the size of the hall is small in relation to the number of people it seats: just over 2,000, giving 6.5 cubic meters of air per person, instead of the ideal 10.

"It's okay for a chamber or choral piece, but symphonies need more air," says Tusquets, who has written several books on the difficulties involved in building the Palau.

Even the location of the Palau was badly chosen. Its magnificent façade cannot be fully appreciated due to the cluster of buildings around it. And until the early 1990s, it abutted with the church of Sant Francesc de Paula, which prevented any expansion of the Palau, as well as interfering with concerts: its bell could often be heard chiming the hours and quarters through quieter pieces.

Tusquets says that for many years he could not understand why Doménech had paid such attention to the exterior façade that gave on to the church: with just three meters separating the two buildings, it could hardly be seen. "But a great architect builds for the eye of God," he says.

Throughout the 1980s, the Palau underwent a gradual process of renewal, until in 1991, the then-bishop of Barcelona was asked if the church of Sant Francesc, which by now had a tiny congregation, could be demolished to give the Palau more room.

A delegation was sent to Rome to discuss the matter with the Pope, and after agreeing to build a new church further out of the city, permission was granted.

The Palau's second salvation was the decision taken at the same time to give the Barcelona City and Catalonia Symphony Orchestra its own concert hall, after sharing the Palau since 1944 with the Catalan Orpheus. The new auditorium was opened in 1999.

Over its century, the Palau has attracted most of the great names of 20th century music, among them Richard Strauss, Enrique Granados, Arnold Schönberg, Artur Rubenstein, Pau Casals, Herbert von Karajan, Leonard Bernstein, Rostropovich, and even Duke Ellington and Ella Fitzgerald. It has always attracted the best. Ravel played here in 1924, while Rodrigo premiered his Concierto de Aranjuez in 1940.

The guided tour finishes with a blast from the German organ, which was restored in 2004. At the end of it, a Japanese tourist timidly asks: "Have the Three Tenors ever performed here?" the guide takes a deep breath and turns, looking down to the stage. "No," he admits, sighing, "the Three Tenors have never played here."

text by El Pais, Agusti Fancelli, Expatica
photos by Montrealais and Flickr contributors malouette and xip