Cadillac led the industry in concealed gas caps, but eventually most of the American automakers joined in the fun.

American automobiles of the 1950s were loaded with whimsical gadgets and gimmicks, but one of our favorites might be the concealed fuel filler. Cadillac pioneered the trend, or so it would appear, when designers tucked away the gas cap under the left tail lamp assembly for the 1941 model year, then continued the practice for years until it became a Cadillac signature item. Originally, the purpose was to clean up and de-clutter the styling, but soon the hidden gas cap became a sort of feature in itself.

Other makes joined in with their own schemes, and eventually there were concealed fuel fillers in endless variety—far too many to include them all here. This is but a tiny sample. No doubt you have some favorite examples of your own, so drop a note in the comments section below and tell us about them.

Not to give away the game entirely, but while the fuel fillers were concealed, they were usually found in the same general area—in or around the left rear lamp assembly. But not always: On the Chrysler Imperial, to name one, it was under the right tail lamp. On the ’58 Oldsmobile above, the gas cap was stashed behind the left lamp bezel.

Here’s where they stashed the fuel filler on possibly the most beloved car of the 1950s, the 1957 Chevrolet. The tail-fin trim hardly seems wide enough to house a filler cap but there it is, behind a spring-loaded door.

In 1952, the Ford Motor Company began tucking the fuel filler behind the rear license plate, which was mounted on a spring-loaded bracket, as on this 1960 Thunderbird convertible. It was a straightforward and logical solution (though not terribly crash-worthy, in retrospect) and a number of carmakers adopted the setup at various times.

On this 1957 Pontiac Chieftain, a base model with modest two-tone paint treatment, the fuel filler is relatively easy to spot. But on the chrome-laden Star Chief and Bonneville, the generous helping of bright metal serves as fairly effective camouflage.

Naturally, Preston Tucker would get in on the act (below). On early examples of his 1948 Tucker 48, the fuel filler was tucked inside the metal grille in the left rear fender (arrow). Later in the 51-car prototype-production run, the fuel tank was moved from the rear to the front to make room for the proposed Tuckermatic automatic transmission with its dual torque converters, and a conventional fuel door was incorporated in the left front fender.