The Ducati Monster (called Il Mostro in Italian) is a muscle bike designed by Miguel Angel Galluzzi and produced by Ducati in Bologna, Italy, since 1993. It is a naked bike, characterized by an exposed engine and frame. The trellis frame in the Ducati Monster is an integral part of the motorcycle's design allowing for both aesthetic appeal and for structural efficiency. In 2005, Monster sales accounted for over half of Ducati's worldwide sales. Ducati motorcycles use 90° V-twin engines, which they call L-twins, with desmodromic valves, and tubular steel trellis frame, designed by Fabio Taglioni (1920–2001).