Yesterday morning there were reports of mercury leaking from a Greenwich Village apartment, which made us wonder if a really huge thermometer broke. The city isn't sure, as they are investigating the matter at 55 West 8th Street, but the Post reports that one theory is "many, many years ago, someone dumped the mercury into a building pipe." To turn the whole building into a thermometer? And mercury is really heavy! The DEP said there was only 15-20 (fluid) ounces of mercury found, but each ounce weighs a pound! While the building was found to be safe, Gothamist cannot imagine how freaky it would have been to see mercury dripping from a ceiling - that's something like a nightmare involving Terminator 2.
The mercury page at Wikipedia is very informative; for instance, we had no idea that mercury was used as a laxative (did the building have some, um, plumbing problems?).