The Erector set was the Lego building set of the early 20th century. Created in 1913 by a Yale-educated doctor, this toy contained a selection of steel girders in various sizes that kids could connect using regular nuts and bolts to craft buildings, bridges, machinery and countless other structures. Like modern building blocks, the components in an Erector set could be disassembled and reused over and over, leading to years of play and learning. Later sets came with electric motors, wheels, pulleys and gears so kids could bring their creations to life, resulting in Ferris wheels that spun at the turn of a crank or steam shovels that could really pick things up.
Toy makers sold more than 30 million Erector sets during the product's first 30 years, largely thanks to one of the first national advertising campaigns used in the toy industry [source: Bass].