I have no idea how advanced these plans are, to build a 65-floor "earthscraper" (an underground, "downward pointed" building) under Mexico, D.F.'s Zócalo (central historic plaza). And I understand people's concerns about building such a thing in such an earthquake prone area (although it's worth noting that during the huge 1985 quake, for example, the subway was actually a pretty safe place to be). So maybe the "earthscraper" is not a serious project. But it would be very cool.