 As the western frontier was further opened up in the latter half of the nineteenth century, the rapidly increasing pace of dinosaur discoveries in the bone-rich badlands of the American Midwest and the Canadian wilderness brought with it a renewed interest in artistic reconstructions of paleontological findings.This "classic" period saw the emergence of Charles R. Knight, Rudolph Zallinger, and Zdeněk Burian as the three most prominent exponents of paleoart.During this time, dinosaurs were popularly reconstructed as tail-dragging, cold-blooded, sluggish "Great Reptiles" that became a byword for evolutionary failure in the minds of the public.