In 1968, the Warsaw Pact invaded Czeckoslovakia and wanted to do the same with Romania. But incredibly they didn't do it, even if Soviets alone massed at least 25 divisions at the borders, not to mention a few Hungarian, Polish and Bulgarian ones. Some kind of “laser” or “plasma” gun was used against them. When Soviets sent their first tank over the border, it was either “melted” or “vaporized”, so they stopped the invasion in its tracks. 1968 is the year when Coanda returned in his native country Romania, bringing with him lots of his personal papers.