According to British newspaper The Guardian, El Ateneo Grand Splendid is the second best bookstore in the world. It preserves the splendour and elegance of the former Gran Splendid theatre/cinema, which was designed by architects Peró and Torres Armengol.
Located in the Recoleta neighbourhood, El Grand Spendid theatre opened in 1919 and immediately became a beacon of porteño culture, hosting ballet, opera, and the first "talkies" shown in Buenos Aires. The national Odeon record label - now owned by EMI - was based here, and singers such as Carlos Gardel recorded on the premises.
https://turismo.buenosaires.gob.ar/en/atractivo/el-ateneo-grand-splendid