Girls und Panzer is an anime that takes place in Japan during an annual holding of what is known as the Sensha-do, or when translated, "The Way of the Tank."
Where other schools might have track meets, kendo, and martial arts tournaments, here girls from all manner of schools from across Japan train in the ways of how to pilot tanks. Tanks from the 1940's during the time of World War II to be exact.
Each school in this universe is depicted as representing one of the major contenders in the second World War (All of which are listed below) and as such, each school has its own flavor of tanks, IE the Black Forest School for Girls (Germany) is primarily made up of Panzers, Tigers, Panthers, and even a Mouse tank, while St. Gloriana Girls High School (Great Britain) consists of mostly English tanks, such as the Churchill heavy infantry tank.
The story follows the actions of Miho Nishizumi who has had bad experiences with the Sensha-do in the past, and in her attempt to escape the contest, she ends up falling headfirst into a crash course in how to pilot one of the most iconic tanks of the Second World War.