July 17 has no owner yet

On July 17, 1945, the leaders of the three great Allied powers — Harry Truman (US), Winston Churchill (UK) and Josef Stalin (USSR) — met in Potsdam, Germany, to decide the future of Europe after the Nazi defeat. During the conference, Truman discreetly informed Stalin of the existence of the atomic bomb, which had just been tested the previous day at Trinity.

On July 17, 2014, Malaysia Airlines flight MH17 was shot down over eastern Ukraine by a surface-to-air missile, killing all 298 passengers and crew on board. International investigations concluded that the missile belonged to the 4th Guards Tank Division of the Russian army. The incident occurred in the midst of fighting between the Ukrainian army and pro-Russian separatists.

On July 17, 1936, General Francisco Franco and other military officers launched the uprising against the Republican government of Spain from Morocco, triggering the Spanish Civil War. The coup, intended to be swift, failed in the major cities but succeeded in parts of the country, leading to a nearly three-year war that caused between 200,000 and 500,000 deaths.