Serendipity is defined as an unplanned event or discovery with a beneficial outcome. The word was coined by English writer Horace Walpole in 1754, in reference to a story called “The Three Princes of Serendip.” The tale recounts the adventures of three princes who make accidental discoveries through luck rather than skill. 

Accidental discoveries are not uncommon in the world of scientific investigation. Many useful substances, including Teflon and Scotchgard, were invented by chemists who were attempting to create something for an altogether unrelated application. (The chemist who invented Scotchgard was a woman? Here are 50 inventions you never knew were invented by women.)

Biochemist and science fiction author Isaac Asimov once said that “the most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ but ‘That’s funny.'” “That’s funny” is exactly what microbiologist Alexander Fleming said when he found that Penicillium mold had contaminated a petri dish and destroyed the bacteria he was experimenting with. His lab accident led to the discovery of penicillin – the world’s first broadly effective antibiotic.

24/7 Tempo has compiled 31 accidental discoveries that changed the world by reviewing sources including History, Reader’s Digest, and Business Insider. In some cases, an initial accidental discovery by one person led to a later invention by another. Only the initial discovery is recounted.

While a few are folk accounts of early discoveries, the majority are inventions and discoveries made by scientists, engineers, doctors, and hobby inventors who were following one path when they stumbled upon another. 

Many serendipitous discoveries have revolutionized the pharmaceutical and medical fields, while others have influenced the worlds of fashion, cosmetics, home appliances, and children’s toys. Some of these happy accidents have drastically improved everyday life. (Here are also 30 NASA inventions we still use everyday.)

Click here to see the accidental discoveries that changed the world