The Cathedral of Our Lady of Mercy stands on the south side of Plaza Rivadavia and has been the religious centre of the city since the late 19th century, though the current neogothic building was completed in the early 20th century. Its twin towers and ornate stone facade give it considerable presence among the relatively modest civic buildings around the square.
Inside, the cathedral is quiet and simply furnished, a welcome escape from the sun in summer. The nave is longer than you might expect from the outside, and the stained glass windows cast coloured light across the stone floors at certain times of day. Free to enter, and generally open throughout the day.