For one United states have more of a roman architecture... Most American homes have columns.
For Puerto Rico they have a Cuban architecture, most houses are made with brick as well with a tiled roofing. Most Puerto Rican use have these gates all around the house on there windows even door which add to the architecture
for United states we have roman architecture every where to the fountains to the marble we use for our counters. As well as United states have a varties of architecture.
As of Puerto Rico since it's A small island its only have its own personal architecture instead of many.
United states have Pre-clumbianand colonial architecture and diffrent cultures mixed together.
Puerto Rico has narrow, winding, cobblestone roads are reminiscent of Andalusia, South of Spain.
Hope this helps a bit.....