You'll probably spot Catedral Metropolitana from a distance before you actually find this grand place of worship. Rest a while inside if the doors are open or just take in the facade from outside.
Catedral Metropolitana is a worthwhile place to begin discovering El Centro. This principal church comes recommended by fellow travelers, but it's not the only spot to see here. Allow some time for other attractions like Obelisco, Colón Theatre, and Casa Rosada to get a complete picture of what the area has to offer.