This is actually about math, and it makes me want to know more about math. It was proposed by Henri Poincaré, a French mathematician, in 1904, and wasn't proved to be correct until just last year. It took mathematicians over 100 years to do that proof! Also, because it was such a difficult conjecture, The Clay Mathematics Institute said that they would award whoever solved the conjecture prize of $1 million. The Russian mathematician, Grigory Perelman, who finally solved the conjecture, actually refused the prize because he knows "how to control the universe," and didn't feel the need to be rich while doing it, apparently.

The conjecture suggests that three-spheres are the only possible bounded three-dimensional spaces to contain no holes. And if that sounds confusing, because it totally is, you can watch the video below, which I found educational and instructive, and actually interesting.