Just northwest of the Obelisco is Plaza Lavalle, three blocks of parks (popular with office workers on their lunch break) surrounded by some important buildings. The most worthwhile sights here are the Teatro Colón and the Teatro Nacional Cervantes, but there's also the neoclassical Escuela Presidente Roca, an educational facility that's often mistaken for Teatro Colón, and across from it, the French-style Palacio de Justicia (1904) housing the Supreme Court.
Plaza Lavalle
Buenos Aires