A megahertz is one million (or 106) hertz.
See hertz, kilohertz (one thousand hertz), gigahertz[?] (109 hertz), terahertz[?] (1012 hertz), and petahertz[?] (1015 hertz).
... their sabotage. They derailed trains, blew up ammunition depots and attacked German garrison. Victory did not come easily. In July 14 in Vercors[?] a newly reinforced ...