A powerful bomb <a href="https://en.wikipedia.org/wiki/1974_Mitsubishi_Heavy_Industries_bombing" id="mwAQg" rel="mw:WikiLink" title="1974 Mitsubishi Heavy Industries bombing">explodes</a> at the <a href="https://en.wikipedia.org/wiki/Mitsubishi_Heavy_Industries" id="mwAQk" rel="mw:WikiLink" title="Mitsubishi Heavy Industries">Mitsubishi Heavy Industries</a> headquarters in <a href="https://en.wikipedia.org/wiki/Marunouchi" id="mwAQo" rel="mw:WikiLink" title="Marunouchi">Marunouchi</a>, Tokyo. Eight are killed, 378 are injured. Eight left-wing activists are arrested on May 19, 1975, by Japanese authorities.