These men are, or at least were until recently, Libyan rebels in battle against the dwindling forces of the now-deceased Muammar Gaddafi. And the red, black and green lump they're standing in front of was once a bulldozer.
It was transformed in the city of Misrata from a plain old earth-mover into a battlewagon: steel-plates sandwich reinforced with concrete. The only views outside were through portholes just big enough for gun barrels and RPGs.
It was built to take Tripoli but wasn't called into action, instead being trekked to Sirte to defend against snipers and push through barricades. Obviously, it didn't fail. There's a vid of the concrete leviathan after the jump.