James Watt invented the very first steam engine.

It's a common misconception that James Watt invented the steam engine. Although Watt made groundbreaking improvements in the 1760s, which drastically increased the machine's efficiency and enabled the Industrial Revolution, the first practical steam engine was actually constructed in 1712 by Thomas Newcomen to pump water out of mines. Watt's version, however, was so much more efficient that it revolutionized industry.