After having seen quite a number of "big & elaborate" cathedrals in the Spanish South America (countries such as Peru, Chile, Argentina & Uruguay) but in Brazil only those which are either big but not elaborate (such as the "main cathedrals" of Porto Alegre & Sao Paulo) or elaborate but "not so big" (not cathedrals but more like smaller churches & monasteries such as the Sao Bentos & Sao Franciscos which are of modest size but quite beautiful inside), it was kind of a "refreshing moment" I would say to be at this church with "both attributes": of a size for it to be termed "a catedral instead of an igreja"; and with elaborateness such as shrines along the length (leading to the altar), colorful art scenes above both along the ceiling & inside the dome, two raised structures like pulpits or such (one on each side of the altar) each supported from underneath by a "winged angel" & also a stairway with its one side just "fully carved" with beautiful scenes.
Coming by metro, Uruguaiana Station (both Lines 1 & 2) is where to get off from which it's just a 5-to-10-minute walk heading east to this church (with its dome clearly visible on one end of the big street right beside the station), and yes actually also should not be missed after this church, by continuing your way north (to the left after coming out from the side of the "big facade") with the way winding through the narrow streets of the old 'centro' part of the city for about 15 minutes, is Sao Bento Monastery with a gold-glittered interior which I would just describe as "quite literally so" (yes a "very worthwhile" site to visit despite its modest size).