Tokyo! It's a busy place, full of buildings, trains and other non-natural objects. Oh, and people. What if something were to wipe out all those people suddenly and left everything else untouched? This.
Deviantartist Tokyogenso's series of paintings where nature reclaims Tokyo is pretty, but it also makes you think - kind of like Megan Fox teaching a course in molecular cell biology. Specifically, it makes you think about whether or not our fight against the planet will ever be won by the planet, someday. My answer: yes, when we invent holodecks and spend all our time inside them.