Operation Barbarossa was the German codename for the invasion of the Soviet Union which began on June 22nd, 1941. When Axis forces moved to take the strategically-important Black Sea port of Odessa, the Soviets put up such a fight as to make the city's ultimate fall costly to the invaders. At the end of a seventy-three day siege and four offensives conducted by the combined German-Romanian force to take the city, over 90,000 Axis members lay dead. The siege would last from August 8th until October 16th, 1941.
As Soviet forces in Odessa fought on to the last, the January Uprising Mechanical Plant within the city retained some of its production facilities that allowed for plant workers to, at the very least, enact repairs on returning, damaged Red Army tanks. This also meant that there were enough facilities to concoct a make-shift Armored Fighting Vehicle (AFV) to reinforce defenses and replace losses to an extent. In the latter case, this gave birth to the "NI" tank - better remembered as the "Odessa Tank" - a diminutive light tank system born out of sheer desperation.
The 7-tonne design was based on the existing, and available, STZ-5 series agricultural tractor which provided the track-and-wheel arrangement needed. Four roadwheels were in play to each hull side with the drive sprocket at rear and the track idler at front. Two track return rollers guided the upper track section along. To this established base was added a simple box structure comprised of mixed metal/wood/rubber construction that provided basic protection for the crew against small arms fire. The operating crew would number three. To complete the design, a traversable turret was set atop the armored hull superstructure. Power came from a single 1MA 4-cylinder gasoline-fueled engine developing 44 horsepower allowing for a top road speed of under 5 mph. Armament was variable and based largely on available stocks found within the city: this meant that machine guns (7.62mm DT series) were typically fitted - one to the turret and another in a bow-mounting. Alternative known armament fits included 37mm mountain guns and 45mm Anti-Tank (AT) weapons - whole turrets taken from other destroyed tanks were sometimes simply remounted to the NI hull.
The initial vehicles arrived in August of 1941 and first combat exposure was had the following month. The NI proved slow and noisy due to their hastily improvised arrangement but they were enough of a confusing initial surprise to the Germans and Romanians to force a temporary pull-back of forces. As many as 70 Odessa tanks may have been completed during the siege but it proved only a temporary measure - the city fell in time and the legacy of the tank itself fell to the history books.
Until 1944, Odessa fell under the rule of the Romanians as part of Transnistria. Tens of thousands of Odessans were murdered by their new overseers and it wasn't until April 10th, 1944 that the city was once again claimed by the Soviets.