From making you gassy at altitude to destroying your toenails, a hard hike can affect you in ways you didn’t foresee.

In honor of the more horrifying aspects of the mortal coil, we bring you a list of nine facts sure to disquiet.

Public spaces are full of surprises, but some moments are so bizarre you can’t help staring, and sometimes laughing, out loud. From people talking to invisible friends on the subway to impromptu dance ...