In the two decades right after the second world war, there was a general feeling of euphoria in the USA, and this was certainly noticeable in the car industry. GM promoted its latest models in a yearly show that traveled all over the country: The Motorama. During those Motoramas, GM displayed several showcars. These cars were intended to test the public's reaction to styling trends and new technologies.
The 1953 Orléans
In 1953 Cadillac introduced two show cars at the Motorama. The first
one was called the Orléans. Many of this car's styling features
were later incorporated in the 1954-1956 model line-up. For instance the
panoramic windshield was first seen on the 1954 Cadillacs. What made the
Orléans really special, was its pillarless hardtop design. The Orleans
was the first American 4 door pillarless sedan. This styling feauture,
so much loved by the American public, would first appear 
on the 1956 Cadillac Sedan de Ville and would be available on this car
until 1976. The Orleans sported suicide doors, i.e. the rear doors
were hinged at their rear ends. Cadillac use these suicide doors on its
1957-1958 Eldorado Brougham, but not on any other production model. Lincoln
on the other hand used suicide doors on its sixties Continental cars. The
Orléans was reminiscent to the 1953 Eldorado from the front end,
is it had a huge amount of chrome on the grille. The rear fender also sported
the fake air scoops, as seen on the other 1953 Cadillacs.The 1953 Le Mans
At the same Motorama, Cadillac also introduced the forerunner of the 1957-1958
Eldorado: the Le Mans. This car was an even more radical change
from the 1953 model style. One has to keep in mind that some manufacturers
were still producing pre-war models, so Cadillac really made a hit with
its futuristic show cars. The Le Mans was a convertible two-seater with
a fiberglass body. Its grille was more refined and its tailfins would be
found back on the 1954 Cadillacs. The panaromic windshield was quite low
and had a strong slope. 
The
Le Mans had no fender skirts, just like the 1957-1958 Eldorados. Even the
finned turbine wheels would appear on those Eldorados (as standard equipment)
and as an option on other Cadillacs. The Le Mans was also a very low car:
it stood 5.5" lower than a regular convertible. Sudden rain showers
are the dread of a convertible owner, who has left his car with the top
down in a parking lot. This fear was over with rain switch on the
Le Mans. This switch was introduced earlier on the Buick LeSabre and now
used in the Le Mans. A grid of electrode wire was used to detect rain drops.
As the water shorted the electrode wires, current was transmitted to the
top motor, which raised the top. It is not known whether the top also locked
into place, or simply folded until it reached the windshield. Cadillac
built a total of 3 Le Mans cars, each one a little bit different.