Did you ever wonder who invented something, and when it was invented? Go to this interactive timeline that highlights inventors/inventions from 1750-1990. Click on the topic to read a brief paragraph about that invention.

Spray-painted subway cars, tagged bridges, mural-covered walls- graffiti pops up boldly throughout our cities. And it turns out: it's nothing new. Graffiti has been around for thousands of years. And across that span of time, it's raised...