The man is a key piece for the independence of Argentina. the building is a key piece for the justice system, inside of it is the Supreme Court of Justice.
Both are really close to the best classic music theater of the world. And the three block square in between called Lavalle Square is really nice place to pass by.
Interesting fact: Infront of the column with the statue of Lavalle, there was a big house of the Dorrego's family, who was acussed of treason and shot by order of Lavalle. Now, both bodies rest in peace next to each orher in the Recoleta's Cementery.