If you're on this page chances are you already know francium is one of the rarest natural elements and that it's so rare, in fact, that if you were to pool every francium atom on planet earth you'd have less than an ounce's worth. The black cloud hanging over this element is its extreme instability. The longest lived isotope has a half life of all of 22 minutes. As actinium (itself an extremely rare element) decays a new francium atom is born only for it too to fall apart... and then only to the even more unstable astatine!

In this cube is the only image ever taken of francium. More precisely, what you're seeing is a false color microphotograph of the heat generated by a bunch of francium atoms corralled together for a family photo. An absolutely tiny amount of francium, the atoms generated here would make a cube 60 atoms to a side and yet the frenetic pace of the suicide taking place in this grouping releases enough energy that its heat is easily visible under a microscope.