At the heart of today's modern bathrooms, the flush toilet is equally rooted in ancient hygiene practices, Elizabethan politics and technology from the Industrial Revolution. Primitive toilets that use a steady stream of water to carry away waste date back at least 5,000 years, and early toilet systems were used by several ancient civilizations, including the Romans and the Indus Valley.

In 1596, Sir John Harington in England described the first modern flush toilet. Harington's installation required a 2-foot-deep oval bowl, waterproofed with bitumen, resin, and wax, and fed by an upstairs cistern. It takes 7.5 gallons of water to flush Harington's pot—a veritable torrent in the days before indoor plumbing.

In 1775, Scottish inventor Alexander Cumming received the first patent for a flush toilet. His biggest innovation was the S-shaped pipe under the toilet, which used water to create a seal that prevented sewer gas from entering through the toilet.

In the late 1800s, a London plumbing manager named Thomas Crapper built one of the first widely successful lines of flush toilets. Crapper didn't invent the toilet, but he did develop the ball valve, an improved cistern filling device that is still used in toilets today.