The Pontiac GTO was an automobile built by Pontiac from 1964 to 1974, and by General Motors Holden in Australia from 2004 to 2006. It is often considered the first true muscle car. From 1964 until midway through 1973 it was closely related to the Pontiac Tempest and for the 1974 model year it was based on the Pontiac Ventura. The 21st century GTO is essentially a left hand drive Holden Monaro, itself a coupe variant of the Holden Commodore.