It was just kind of a "welcoming change", I would say, after walking along the streets of the city's area with mostly heritage-styled buildings (likely its downtown which was not too crowded but still in a "close proximity" to buildings as can be expected being in like a city's core) to arrive at this impressive-sized plaza (likely "more a rectangle" than a square): where right about at the center is a fair-sized fountain with a "raised platform" right beside the fountain (for some good 360-degree viewing of the Plaza while leaning against the platform's railings), where also at about the center is a national flag (pretty-good-sized to look up above), and where also seen at the time (but yes likely a "usual scenario") just quite spread out over the Plaza's ground area were a "huge swarm" of pigeons with actually also kind of not surprisingly an outdoor vendor for pigeon food right nearby. And yes, to do in conjunction with this plaza (for about a half-day sightseeing in total) are Catedral Metropolitana on the Plaza's east side (with a pretty great "decorative interior" of nice paintings & these super-sized medals kind of a "unique feature" the likes of which I have seen at no other cathedral) and Palacio Nacional on the Plaza's north side (with 2 levels of a "fairly impressive" interior with some stairway murals, beautiful rooms & miscellaneous displays). Also, quite conveniently located in a close vicinity "pretty much right around" this plaza are Mercado Central (for all various Guatemala souvenirs and also with a food court for "local meals") and fast-food places such as McDonald's & Pizza Hut.
Among the "main plazas" of South & Central Americas (with one in every capital & also some smaller cities), I was impressed most by "3 of them" one of which being this plaza (along with those of Bogota & Mexico City) for their wide-open spaciousness not just due to the size but also taking into account being uncluttered by things such as trees & flower beds (as is the case at some plazas making them less wide-open).