9. Bigfoot
Over the decades, many people claim to have seen animal footprints shaped like human feet known as "Bigfoot". Even so, no giants have been found yet. No giant has ever lost its life to a hunter's gun, a car accident, or disease. Because there is no concrete evidence such as teeth or bones, people use eyewitness accounts, vague photos or videos to prove the existence of giants. Theoretically, scientists cannot prove that giants or Loch Ness monsters exist, but proving the opposite is also impossible. According to Livescience, those large creatures may exist, but they always avoid humans.