If you took out all of the empty space from between and within the atoms making up each human being, the entire human race would fit into the volume of a sugar cube. – WTF Fun Facts
Source: http://www.scienceabc.com/pure-sciences/can-the-entire-human-race-fit-inside-a-sugar-cube.html
Your tooth enamel is harder than a lobster’s shell or a rhino’s horn. It’s even harder than steel. It’s made of mineralized calcium phosphate, which is the hardest substance a living being can produce. – WTF Fun Facts
Source: https://en.wikipedia.org/wiki/Tooth_enamel