Live Science's Jeanna Bryner contributed to this countdown, which was originally published on March 6, 2012.
Before the invention of the wheel in 3500 B.C., humans were severely limited in how much stuff we could transport over land, and how far. Apparently the wheel itself wasn't the most difficult part of "inventing the wheel." When it came time to connect a non-moving platform to that rolling cylinder, things got tricky, according to David Anthony, a professor of anthropology at Hartwick College.
"The stroke of brilliance was the wheel-and-axle concept," Anthony previously told Live Science. "But then making it was also difficult." For instance, the holes at the center of the wheels and the ends of the fixed axles had to be nearly perfectly round and smooth, he said. The size of the axle was also a critical factor, as was its snugness inside the hole (not too tight, but not too loose, either).
The hard work paid off, big time. Wheeled carts facilitated agriculture and commerce by enabling the transportation of goods to and from markets, as well as easing the burdens of people traveling great distances. Now, wheels are vital to our way of life, found in everything from clocks to vehicles to turbines. [Read more about the invention of the wheel]
Next: The nail
Without nails, civilization would surely crumble. This key invention dates back more than 2,000 years to the Ancient Roman period, and became possible only after humans developed the ability to cast and shape metal. Previously, wood structures had to be built by interlocking adjacent boards geometrically a much more arduous construction process.
Until the 1790s and early 1800s, hand-wrought nails were the norm, with a blacksmith heating a square iron rod and then hammering it on four sides to create a point, according to the University of Vermont. Nail-making machines came online between the 1790s and the early 1800s. Technology for crafting nails continued to advance; After Henry Bessemer developed a process to mass-produce steel from iron, the iron nails of yesteryear slowly waned and by 1886, 10 percent of U.S. nails were created from soft steel wire, according to the University of Vermont. By 1913, 90 percent of nails produced in the U.S. were steel wire.
Meanwhile, the screw a stronger but harder-to-insert fastener is thought to have been invented by the Greek scholar Archimedes in the third century B.C.
Next: The compass
The Chinese invented the first compass sometime between the 9th and 11th century; it was made of lodestone, a naturally-magnetized iron ore, the attractive properties of which they had been studying for centuries. (Pictured is a model of an ancient Chinese compass from the Han Dynasty; it is a south-indicating ladle, or sinan, made of polished lodestone.) Soon after, the technology passed to Europeans and Arabs through nautical contact. The compass enabled mariners to navigate safely far from land, increasing sea trade and contributing to the Age of Discovery.
Next: Printing Press
With this movable type process, printing presses exponentially increased the speed with which book copies could be made, and thus they led to the rapid and widespread dissemination of knowledge for the first time in history. Twenty million volumes had been printed in Western Europe by 1500.
Among other things, the printing press permitted wider access to the Bible, which in turn led to alternative interpretations, including that of Martin Luther, whose "95 Theses" a document printed by the hundred-thousand sparked the Protestant Reformation. [Read more about Johannes Gutenberg and the Printing Press]
Next: The internal combustion engine
Pictured are the operating steps of a four-stroke internal combustion engine. The strokes are as follows: 1) Intake stroke - air and vaporised fuel are drawn in. 2) Compression stroke - fuel vapor and air are compressed and ignited. 3) Power stroke - fuel combusts and piston is pushed downwards, powering the machine. 4) Exhaust stroke - exhaust is driven out.
Next: The telephone
Though several inventors did pioneering work on electronic voice transmission (many of whom later filed intellectual property lawsuits when telephone use exploded), Alexander Graham Bell was the first to be awarded a patent for the electric telephone in 1876. (His patent drawing is pictured above.) He drew his inspiration from teaching the deaf and also visits to his hearing-impaired mom, according to PBS. He called the first telephone an "electrical speech machine," according to PBS.
The invention quickly took off, and revolutionized global business and communication. When Bell died on Aug. 2, 1922, according to PBS, U.S. telephone service stopped for a minute to honor him.
Next: The light bulb
As well as initiating the introduction of electricity in homes throughout the Western world, this invention also had a rather unexpected consequence of changing people's sleep patterns. Instead of going to bed at nightfall (having nothing else to do) and sleeping in segments throughout the night separated by periods of wakefulness, we now stay up except for the 7 to 8 hours allotted for sleep, and, ideally, we sleep all in one go. [Read more about the invention of the light bulb]
Penicillin was being mass produced and advertised by 1944. This poster attached to a curbside mailbox advised World War II servicemen to take the drug to rid themselves of venereal disease.
About 1 in 10 people have an allergic reaction to the antibiotic, according to study published in 2003 in the journal Clinical Reviews in Allergy and Immunology; even so most of those people go on to be able to tolerate the drug, researchers said.
Natural and herbal contraception has been used for millennia. Condoms came into use in the 18th century, while the earliest oral contraceptive "the pill" was invented in the late 1930s by a chemist named Russell Marker.
Scientists are continuing to make advancements in birth control, with some labs even pursuing a male form of "the pill." A permanent birth-control implant called Essure was approved by the Food and Drug Administration in 2002, though in 2016, the FDA warned the implant would need stronger warnings to tell users about serious risks of using Essure. [7 Surprising Facts About the Pill]
Next: The Internet