They represent the evolution of the vehicle (particularly the tail fins) between 1949-1963. All were old running or junk cars at the time. They have survived these 40 years and are spray-painted by visitors (which is welcomed). Hundreds (if not thousands) of spray paint cans litter the entire area.
It's pretty crazy! And every time we drove by there (which was almost every day as the Oasis RV Resort is about 1/2 mile from it), there were cars, trucks, motorcycles, or RVs parked along the road to check it out from morning until night.
We didn't take any spray paint with us but are considering a second visit to keep with the tradition.
A half-mile down the road is a small gift shop (not really worth the visit unless you want to buy a t-shirt). But there are three Cadillacs on display there that are pretty cool.
The first was owned by Elvis Presley, the second by Willie Nelson, and the third by John Wayne.
Admission: Free, of course!