Here's a fun fact; the vast majority of supposed "facts" told in threads like this one are absolute and utter fucking bullshit.
Humans don't eat spiders while sleeping, nowhere in the US is pi 4, plenty of primates also enjoy sex, there is no evidence that Hitler had only one ball, the great wall of china is not visible from the moon by the naked eye, the duck's quack does in fact echo, goldfish do not at all have a memory span of only a few seconds, the misconception that lemming mass-suicide took place did not originate with Disney, glass is not a liquid, there is absolutely no evidence whatsoever that sugar causes hyperactivity in children, and a penny falling from the top of the Empire State Building will cause no injury whatsoever to a person being struck by it.
Note that I will start slapping anyone bringing up any further false factoids.