10 Scientific Breakthroughs We Literally Couldn't Live Without

The use of antibiotics has dramatically reduced the mortality rate linked to certain diseases. iStock/Thinkstock

For most of human history, virtually everyone on the planet faced the risk of dying in epidemics of bacterial diseases that sometimes ravaged multiple continents. One such disease, bubonic plague -- the "Black Death" -- killed an estimated 200 million people in the 14th century alone [source: BBC].

Then, in the late 1920s, a London physician named Dr. Alexander Fleming, who was trying to develop an antibacterial agent, noticed mold that had contaminated a petri dish inhibited the growth of a pathogen he was studying. Fleming published a scientific article on his discovery in 1929, and one of his students, Dr. Cecil Paine, eventually became the first clinician to demonstrate the effectiveness of penicillin, a drug derived from the mold, against bacterial disease in human patients [source: Wong]. Since then, the use of penicillin and other antibiotics has led to reductions in the mortality rate from certain infections like syphilis, septicemia and, of course, bubonic plague [source: Hemminki and Paakkulainen]. Interestingly though, antibiotics can't claim all the credit when it comes to decreased mortality rates in common bacterial diseases. Other breakthroughs on our list, like clean water, have a big role to play, too [source: Hemminki and Paakkulainen].