My Munich transit notes will take a while to settle, but meanwhile, Munich's U-bahn station Münchner Freiheit is a must-see for all visitors.
U-bahn lines have associated colors that are reflected in both mapping and signage. (See U-bahn map here). This station is an interchange between lines 3 (orange) and 6 (blue). So the architects had a field day exploring all the ways that orange and blue can converse, or clash. And as if orange weren't garish enough, they invented a peculiar pea green to dance with it.
This is, by the way, a weaved station: U3 and U6 northbound on one platform, and both southbound on the other, to maximize cross-platform transfers. U6 is toward the center of the station in both directions, so to express that you have the blue pillars down the center, with the curious orange+olive on both outside walls, where the (orange) U3 runs.
A mirrored ceiling festooned with semi-protruding panels of flourescent light amplifies the dissonance.
This may well the the brightest underground station I've ever seen, bright not just with brute-force flourescents but with a mirror-intensive design that recycles light. The photons can bounce around pretty much forever.
Munich has several recent U-bahn stations that show some real architectural panache, but this is the only one that's truly fun. Would it get old looking at this every day? I don't think so.