This is the most successful tank ever fielded --- the Sturmgeschütz IIIG Tank Destroyer (or "Assault Gun", depending on whom you ask) destroyed more than 20000(!) enemy tanks by 1944.

Today, it would be shocking for any army in the world to even HAVE 20000 tanks...

Are you sure , i mean the stug III is just an normal originality for infantry support build tank not an badass tank-killing machine with the most powerful gun on the world and impenetrable amour . Okay i just looked at the building numbers of also 12k what makes still an kill ration over 1.0 . ( includes the first versions plus the StuH ) Of the G version were build about 8000 , okay from that view it looking a lot better .

There's no mistake --- over 20000 tanks were destroyed by the StuG III.

...and I've got proof:
http://en.wikipedia.org/wiki/Sturmg.....ch%C3%BCtz_III

http://www.stugiii.com/sturmartillerie.html

http://www.achtungpanzer.com/sturmg.....eschutz-iv.htm

Also responsible for the most tanks killed by any one tank design ;)

Great stuff.