This article was originally published on October 19, 2015. To read the stories behind other celebrated architecture projects, visit our AD Classics section.

The Bank of London and South America (Banco de Londres y América del Sud, or BLAS) in Buenos Aires defies convention and categorization, much like the architect primarily credited with its design, Clorindo Testa. A unique client relationship, guided by the bank’s staff architect Gerald Wakeham, and a supportive collaboration with the firm Sánchez Elía, Peralta Ramos and Agostini (SEPRA) resulted in a building that continues to evoke surprise and fascination.