1939 Pontiac Ghost Car commands $308,000 at auction

Part of the Previews of Progress pavilion in which General Motors' Futurama showed off what was to come in the world of autos, the 'invisible' Pontiac is credited as the first transparent car in America.

And there were no shortcuts taken with its body: the Plexiglass form was fabricated by the company that brought the material to market in 1933, Rohm & Haas.

The see-through sedan was sold at RM Auctions' St. John's auction in Michigan on July 30, fetching $308,000. Not bad appreciation for a domestic oddity that cost $25,000 to build when new.