Here are a list of dates that appear on our time line.
Ancient:
~590 BC Romans held circus events with a seesaw; Germans, Polyneasons, Egyptians, Greeks, and Chinese also had seesaw
Modern:
1945 Richard James invents the Slinky® on accident
1955-1975 the Slinky® is used a makeshift radio antena when tossed over tree branches
