The church in question is the Argentinian national church and was founded by the Argentinian, Msgr. José León Gallardo. Construction on the church lasted from 1910 until 1930 and the architect of record for the project was Giuseppe Astorri. As part of his design, he included an impressive bell tower that the average passer-by could be forgiven if they mistook for being medieval.
The facade itself is similarly antique in its look and feel, complete with a decorated facade by Giovanni Battisti Conti showing a depiction of the Lamb and the Seven Seals of Revelation surrounded by symbols of the Four Evangelists. Beneath are seen four date palm trees and twelve lambs, representing the twelve apostles. It is worth noting that in terms of the mosaics and other such depictions in the church, there was no attempt to create any faux primitivism. Rather, the stylistic manner of the depictions are recognizable to their own time, but the template from which it is drawn comes from the Italo-Byzantine tradition.
The decorated facade continues downward to the entrance of the church which also includes two Ionic columns and beautiful marble revetments in the portico. Ancient style transennae were used for the windows (the windows themselves being made of alabaster rather than glass). Above the main door are two peacocks -- popular paleochristian symbols of eternal life.
To round out our considerations of the exterior, here is a view from the back, looking at what would be the outside of the apse.
Turning to the interior, we will find more of the same. The template is that of a Roman basilica, complete with an open timber, trussed ceiling, a central nave lined by columns and two side naves going down either side of these. An ancient, cosmatesque style ambo is likewise to be found, along with a balustrade separating the presbyterium from the nave. A ciborium covers the high altar and marble revetments clothe the apsidal walls behind the altar.