The "Paris Gun" was one of Germany's several "big guns" featured during World War 1. It was originally a 380mm gun barrel (38cm SK L/45 "Max") used on the "Long Max" series of railroad guns developed by the storied concern of Krupp though the assembly now lengthened and its barrel lined to produce a longer-range weapon of smaller 210 caliber. The 69-foot long barrel, and complex mounting hardware, sat atop a specially-configured railway car and its crew numbered 80 specialists and assistants - these personnel pulled from the ranks of the German Navy as the gun held a naval origin. With the arrival of the Paris Gun, however, the Germans produced a weapon that could launch a man-made projectile into the stratosphere - up to 26 miles up - the first such act of its kind recorded in astronautics.
As its name suggested, the weapon was developed with the sole intent to engage Paris at long range, proving to its citizens that they were not immune to the fighting along the Western Front. In this way, the gun proved a success as a psychological terror weapon but was largely inaccurate, prone to technical issues, and required many resources which then produced limited results. In this way, the Paris Gun was something of a failure as a true battlefield artillery piece.
The Paris Gun made use of a hefty 234lb projectile and held a range out to 81 miles. Within German-held territory in France, the weapon was able to target Paris which lay some 75 miles away. It opened up in anger against the city on March 21st, 1918 and continued its terror campaign into August of that year, withdrawn amidst the advancing Allied forces. During its operational tenure, it managed to fire at least 320 shells, kill 250 Perisians, and injure a further 620 citizens while accounting for considerable damage from the 210 shells. The weapon typically operated alongside a battery of standard German guns to help shield its position from wandering Allied reconnaissance aircraft and ground scouts. As such, its true location alluded the Allies for some time. Initially, its projectiles were thought to have been derived from a passing German bomber or Zeppelin until fragments were studied more closely and shown the true artillery origins.
Krupp manufactured seven 210mm barrels for the Paris Gun program as fracturing and wear were constant issues when dealing with such forces at play. The retreating Germans then elected to have the weapon completely destroyed lest it fall into enemy hands - not even its design plans survived the fighting.
Such ended the reign of terror on Paris brought through the German "Paris Gun".