During the 1950s, a number of "dream cars" were built by Packard in an attempt to keep the marque alive in the imaginations of the American car-buying public. Included in this category are the 1952 Pan American that led to the production Caribbean and the Panther (also known as Daytona), based on a 1954 platform. Shortly after the introduction of the Caribbean, Packard showed a prototype hardtop called the Balboa. It featured a reverse-slanted rear window that could be lowered for ventilation, a feature introduced in a production car by Mercury in 1957 and still in production in 1966.