"What are continents?"

(CBS) - Pop quiz: how many continents are there? Seven? Five? You're all right and you're all wrong. As this informative video explains, the definition of "continent" is hardly definitive.

Apparently, nailing down the number of continents is harder than one would think. Even this video doesn't have an answer! Come on, C.G.P. Grey, don't leave us hanging.

Oh well, at least we'll always have the excellent explanation of what exactly the United Kingdom is.