Washington Metro.

Designed by the Chicago architect Harry Weese- these metro stations remains as a good example of Brutalist architecture which was spawned from the modernist architectural movement between 1950s to the mid 1970s.

(Heavy usage of concrete and repetitive design motifs)

This is known as the second-busiest metro system in the United States after the New York City Subway, and I was able to take advantage of this well planned and organized system for the past four days.