The building opened in May 1919 as the Teatro Gran Splendid, designed by the architects Peró and Torres Armengol for the impresario Max Glücksmann, a film and recording entrepreneur who shaped much of early Argentine show business. It was built to dazzle. An audience of roughly 1,050 could fill its tiers to watch ballet, opera, musical performances, and tango on the stage below. The Italian artist Nazareno Orlandi painted the soaring ceiling frescoes, an allegory of music and peace that still draws every visitor's gaze upward, and the sculptor Troiano Troiani carved the caryatids that stand guard over the hall. In an age when Buenos Aires saw itself as the Paris of South America - and spent like it - the Grand Splendid was proof of the ambition, a temple to spectacle in the heart of Barrio Norte, its plush and gilt a statement that this young city on the Río de la Plata could match the grand houses of Europe.

The theatre was not only a stage; it was a recording studio at the dawn of the recorded-sound era. The Odeon record label operated from the building, and the legendary tango singer Carlos Gardel - the voice that defined the music for generations of Argentines - recorded here. In 1923 the venue gave birth to its own radio station, LR4 Radio Splendid, broadcasting from inside the building. As the silent era gave way to sound, the Grand Splendid changed with it, converting to a cinema and, in 1929, screening some of the first sound films ever shown in Argentina. For decades this single address sat at the crossroads of nearly every way a city could be entertained: live performance, recorded music, radio, and film.

By the turn of the millennium the theatre needed a new purpose, and in the year 2000 it found an unlikely one. Under the direction of architect Fernando Manzone, the building was carefully converted into a bookshop rather than gutted for one. The cinema seating came out and bookshelves went in, but the bones of the theatre stayed: the frescoed dome, the ornate carvings, the crimson stage curtains, the auditorium lighting, the intact theatre boxes. Spanning some 2,000 square meters, El Ateneo Grand Splendid became the flagship of its bookselling group. In 2007 alone it sold more than 700,000 books, and over a million people now pass through its doors each year - many of them, frankly, to look rather than to buy.

The world noticed. In 2008 The Guardian ranked it the second-most beautiful bookshop on the planet, and in 2019 National Geographic went further and crowned it the most beautiful bookstore in the world. The genius of the place is in what survived. Customers settle into the old theatre boxes to read, drawing the crimson curtains of their private balcony around them. The café at the back occupies the very stage where Gardel once stood, so a reader can sip coffee where an orchestra once tuned up, beneath the same lights that once dimmed for a performance. Tourists wander the aisles with their heads tipped back, photographing the dome more than the shelves. Despite a century of reinvention - opera house, recording studio, radio station, cinema, bookshop - the building has never stopped feeling like the grand theatre it was born as. The performance simply changed. Now the audience reads, and the show is the room itself.