Scientist Stephen Hawking was known for his groundbreaking work with black holes and relativity, and was the author of several popular science books including 'A Brief History of Time.'

Happy 20th Birthday, Google! Created by Larry Page and Sergey Brin as a research project at Stanford, they called the search engine "Google" after the mathematical term "googo." The term refers to the No. 1 followed by 100 zeros, to reflect their mission to organize the immense amount of information available on the web.

Alice Ball was an African-American chemist who developed the first successful treatment for those suffering from Hansen’s disease (leprosy).

Jane Goodall created one of the most trailblazing studies of primates in modern times when she dwelled with Tanzanian chimps to observe their behavior.

Marie Curie was the first woman to win a Nobel Prize, in Physics, and with her later win, in Chemistry, she became the first person to claim Nobel honors twice.

Elizabeth Blackwell was the first woman to graduate from medical school in the United States. She became a leading public health activist during her lifetime.

Florence Nightingale was a trailblazing figure in nursing who greatly affected 19th- and 20th-century policies around proper care. She was known for her night rounds to aid the wounded, establishing her image as the 'Lady with the Lamp.'

Mathematician Mary Jackson was one of a small group of African-American women who worked as aeronautical engineers, called "human computers," at NASA during the Space Age.

Dorothy Johnson Vaughan worked as a mathematician on the SCOUT Launch Vehicle Program that launched America’s first satellites into space.

Daniel Hale Williams was one of the first physicians to perform open-heart surgery in the United States and founded a hospital with an interracial staff.

African-American chemist Percy Julian was a pioneer in the chemical synthesis of medicinal drugs such as cortisone, steroids and birth control pills.

Astrophysicist Neil deGrasse Tyson hosted NOVA ScienceNow and makes media appearances to encourage science and space exploration.

Earnest Everett Just was an African-American biologist and educator best known for his pioneering work in the physiology of development, especially in fertilization.

Henrietta Lacks is best known as the source of cells that form the HeLa line, used extensively in medical research since the 1950s.

Marie M. Daly is best known for being the first African-American woman to receive a Ph.D. in chemistry in the United States.

Ralph Bunche was a Nobel Peace Prize–winning academic and U.N. diplomat known for his peacekeeping efforts in the Middle East, Africa and the Mediterranean.

Prussian physician Robert Koch is best known for isolating the bacterium which causes tuberculosis, the cause of numerous deaths in the mid-19th century.

Charles Darwin is best known for his work as a naturalist, developing a theory of evolution to explain biological change.

Astronomer Nicolaus Copernicus was instrumental in establishing the concept of a heliocentric solar system, in which the sun, rather than the earth, is the center of the solar system.

Biologist Alfred Kinsey wrote Sexual Behavior in the Human Male, which was based on research he and his colleagues conducted at the Institute for Sex Research.

Gregor Mendel was an Austrian monk who discovered the basic principles of heredity through experiments in his garden. Mendel's observations became the foundation of modern genetics and the study of heredity, and he is widely considered a pioneer in the field of genetics.

George Washington Carver was a prominent African-American scientist and inventor. Carver is best known for the many uses he devised for the peanut.

James D. Watson is a Nobel Prize-winning biophysicist and researcher credited with co-discovering the double-helix structure of DNA.

Scientist Louis Pasteur came up with the food preparing process known as pasteurization; he also developed vaccinations for anthrax and rabies.