tinted side window glass and painting or molding the outer side of each pillar in black to make them less visible, creating a hardtop look without actually omitting the pillar. Some mid- to late-1970s models continued their previous two-door hardtop bodies, but with fixed rear windows or a variety of vinyl roof and opera window treatments. By the end of the 1990s, almost all hardtop designs were discontinued as structural integrity standards continued to increase. Hardtops were typically more expensive than regular sedan models when new. They are more collectible than standard models of the same vehicle, which have a B-pillar. Origins Early automobiles had no roof or sides, but by 1900 several cars were offered with fabric roofs and primitive folding tops. However, cars with fully closed bodies (i.e. with a rigid roof and sides) grew in popularity and soon became the norm. In 1915–1918, the first pillarless hardtop cars were produced, then called "convertible cars" (or "touring sedans" or "Springfields"). The Springfield design featured folding upper frames on the doors and the rear glass frames are removable and stored under or behind the seats. In the late teens, Cadillac offered a sedan with removable "B" pillars. Another form of early pillarless hardtop is the "California top", originating in Los Angeles and most popular from 1917 to 1927. These were designed to replace the folding roofs of touring cars, in order to enclose the sides of the car for better weather protection. One objective of these aftermarket tops was to bring the cost of the closed car nearer to the prices of corresponding open cars. Automobile dealers were encouraged to equip an open car with a California top to demonstrate that they were "cool and clean in summer, and warm and dry in winter." The hard tops were frequently equipped with celluloid windows that retracted like a roller blind for open sided motoring offering a low-cost compromise between an open and closed car. United States There were a variety of hardtop-like body styles dating back to 1916. Chrysler Corporation built seven pillarless Town and Country hardtop coupes as concept vehicles in 1946, and even included the body style in its advertising that year called the Town and Country Custom Club Coupe. In 1951, Plymouth offered the Cranbrook Belvedere as a low priced hardtop two-door until 1953. Mass-production of hardtops began with General Motors, which launched two-door, pillarless hardtops in