Even more interesting, these mass disappearance events are on record going back hundreds or thousands of years. In the age of the Internet and “eyes” everywhere, perhaps the mystery of such disappearances will soon be solved. Even more bizarre, the stone markers were neatly placed in two piles on each side of the graves. The word may have been hastily left as an indication of who was responsible for the mass disappearance. [5]5 Anasazi TribeLate 1200sThe Anasazi tribe is regarded as one of the most sophisticated civilizations of the North American continent.