If ancient aliens visited Earth, what was their legacy, and did they leave behind clues that exist in plain sight such as sophisticated aircraft, complex electrical grids, and intricate construction machinery? Indian Sanskrit texts, dating back to 6000 B.C., describe in varying but vivid detail flying machines called Vimanas.If ancient aliens visited Earth, what was their legacy, and did they leave behind clues that exist in plain sight such as sophisticated aircraft, complex electrical grids, and intricate construction machinery? Indian Sanskrit texts, dating back to 6000 B.C., describe in varying but vivid detail flying machines called Vimanas.