`1_point_21_gigawatts` [Thread]

One of the greatest reddit threads of all time, with 7059 comments, is a
gold mine of this stuff:

http://www.reddit.com/r/AskReddit/comments/izm57/what\_do\_you\_consider\_to\_be\_the\_greatest\_unsolved/

  [Thread]: https://reddit.com/r/AskReddit/comments/q0sgj/what_is_a_mystery_that_creeps_you_out_the_most/c3tur66/