By Joe Rachman
What sparked the craze for martial arts, particularly kung fu, in 1970s America? Why did some Serbs commit acts of genocide in the late twentieth century despite Serbs themselves having been victims of genocide during World War Two? What started the Opium Wars? Did Zarathustra, the supposed founder of Zoroastrianism, actually exist? Why are contemporary African states so poor when compared to the legendary wealth of some pre-colonial African empires? All these questions, and more, posed by curious members of the public have recently been answered for free by historians willing to dedicate a little bit of their time to help sate public curiosity about history. Welcome to /r/AskHistorians.