2. Slinky (1945)
The Slinky was invented by accident in the early 1940s by Philadelphia naval engineer Richard James, who was working to develop stabilizers for ship equipment in rocky seas. James and his wife, Betty, first displayed the creation in a Gimbels department store in 1945. The store instantly sold out its entire Slinky inventory, moving all 400 units in under an hour and a half. The Jameses sold 100 million Slinkys, for $1 apiece, over the next two years.
Since then, over 300 million Slinkys have been sold worldwide. The toy is also available in colored plastic versions and as pull toys with Slinky bodies, like the
Slinky Dog in the “Toy Story” movie franchise. The Slinky is the official state toy of Pennsylvania, and the US Postal Service issued a Slinky postage stamp in 1999.