#4 The lost crew of Mary Celeste
The Mary Celeste was a ghost ship which was found in 1872. Chemist Dr. Andrea Sella experimented and found that there were other ships as well, all of them caught fire, so warriors could’ve abandoned them by perishing into the sea.
#5 The ancient Egyptian helicopter
Abydos hieroglyphs in the temple of Osiris caused some great debates about the existence of helicopters, tank and even jet among them. Scientists recently found that the designs are tweaked, and they aren’t real.