Thomas Alva Edison   Menlo Park, New Jersey, 1879.

Thomas Edison pioneered so many technologies - from recording music to primitive refrigerators - but perhaps the one that's had the most impact on our day-to-day lives is the simple light bulb. Before Edison's invention, people burned candles to produce light. They were messy, they flickered, and they didn't produce enough light for comfortable reading. Now all you have to do is flick a switch. Maybe that's why cartoons often use a light bulb as the symbol for a good idea.