Hitler and the Nazi staff were exceptionally interested in ancient India and Tibet and sent expeditions to both these places yearly, starting in the 30's, in order to gather esoteric evidence that they did so, and perhaps it was from these people that the Nazis gained some of their scientific information! According to the Dronaparva, part of the Mahabharata, and the Ramayana, one Vimana described was shaped like a sphere and born along at great speed on a mighty wind generated by mercury. It moved like a UFO, going up, down, backwards and forwards as the pilot desired. In another Indian source, the Samar, Vimanas were "iron machines, well-knit and smooth, with a charge of mercury that shot out of the back in the form of a roaring flame."
Another work called the Samaranganasutradhara describes how the vehicles were constructed. It is possible that mercury did have something to do with the propulsion, or more possibly, with the guidance system. Curiously, Soviet scientists have discovered what they call "age old instruments used in navigating cosmic vehicles" in caves in Turkestan and the Gobi Desert. The "devices" are hemispherical objects of glass or porcelain, ending in a cone with a drop of mercury inside. It is evident that ancient Indians flew around in these vehicles, all over Asia, to Atlantis presumably; and even, apparently, to South America.