What was the name of the largest tank battle in history?

The Panzerkampfwagen VIII, codenamed Maus("mouse" ... who says the Nazis didn't have a sense of humor?), was the largest tank ever built (as a prototype ... an additional hull without turret was also completed).

Larger tanks such as the Landkreuzer P-1000 Ratte ("rat"), about five times larger than the Maus, have been designed but never actually built. Even the Maus was really too large and unwieldy to be of any real practical use.