The Wikipedia article of the day for April 6, 2017 is 7th Army (Kingdom of Yugoslavia).
The 7th Army was a Royal Yugoslav Army formation, raised three days before the German-led invasion of Yugoslavia of 6 April 1941, during World War II. On the first day of the invasion, the army's commander Dušan Trifunović was alarmed when the 4th Army, on the right flank of the 7th, was undercut by fifth column activities by Croats within its major units and higher headquarters. The Germans captured Maribor two days later and expanded their bridgeheads, supported by the Luftwaffe. On 10 April, the German 14th Panzer Division captured Zagreb. Italian offensive operations began the following day, with thrusts towards Ljubljana and down the Adriatic coast, capturing more than 30,000 Yugoslav troops near Delnice. When fifth column supporters of the Croatian nationalist Ustaše movement arrested the headquarters staff of the 7th Army later that day, the formation effectively ceased to exist. On 12 April, the Germans linked up with the Italians near the Adriatic coast, encircling the remnants of the 7th Army, which offered no further resistance. Ceasefires were implemented on 15 April, and the Yugoslav Supreme Command surrendered unconditionally.