"Avalanche" system for Russian OMON (special police)
Our pal Avi Abrams Dark Roasted Blend blog has a round-up of riot control vehicles from around the world, including a brief history of how they came to be:
It all started in Germany, in 1931. The first anti-protest vehicle equipped was built on Mercedes chassis, and already had a large water cistern in the back and a rotating turret with water-cannon. In the following years (especially after creation of West Berlin) Germany built so many of these trucks, that police forces often used them to deliver water to nearby suburban areas.
During the 70s and 80s the "popularity" of such machines increased due to their extensive employment in West Berlin, Chile and Algeria. Many repressive regimes began to pre-order these models from mostly European manufacturers, for various (mostly nefarious) uses.