Quick trip through several countries, starting in Buenos Aires. Stayed in Montevideo
Plaza Independencia... we stayed a few blocks from here. Very close to ferry terminal and lots of pedestrian friendly stuff to see nearby.
Mercado Agrícola de Montevideo... huge indoor market. A bit touristy but some cool stalls there nonetheless. We tried some Yerbe Mate ice cream which was... interesting.
Punta Carretas prison, opened in 1910, held political prisoners for decades. It was converted to a shopping mall in 1994... so, kind of still a prison I suppose.