Käthehirt Valley is a place that appears in Metal Slug: Super Vehicle-001. Mission 3: Iron Cavalrymen in Hell takes place here. This mission is where the Regular Army fights Allen O'Neil for the first time ever.
It is a valley held by a Rebel Armored Division composed of Iron Isos, Rebel Infantrymen, Di-Cokkas and Girida-Os. Judging by its snowy landscape and the large amount of Rebel tanks in the current area, it could be based off the Battle of the Ardennes or Operation Barbarossa in World War II.
Villeneuve Mt. System | Ronbertburg City | Käthehirt Valley | Ridge 256 | Gerhardt City | Straits of Traven | Saudi Arabia | Egypt | Rebel Supply Train | Hong Kong | New Godokin City | Rebel Siberian HQ | Rugname | Dr. Moureau's Island | Airplane Crash Site | Rebel's Secret Factory | Desert Ruins | Amadeus Mainframe Base | Corridor of Fire | New York | Osaka | Pekin | Meteor Crash Site | Garbage Island