Avenida 9 de Julio

Basically an Argentinian version of Washington's National Mall, but surely that terrible description didn't express it very well. This street, Avenida 9 de Julio (or "July 9 Avenue", I assume), contains a monumentally monumental monument, the Buenos Aires obelisk. Also lined with many other buildings that I'm sure are of interest, it would be a high-priority stop if I was in the Buenos Aires area.