Sina Shahbazmohamadi places a 3-D printed copy of a recorder foot joint into a measuring device in a lab at the University of Connecticut's Center for Clean Energy Engineering. Peter Morenus/UConn hide caption

itoggle caption Peter Morenus/UConn

Once the roots of the Eskimo potato got too tough to eat, Christopher McCandless started collecting the seeds in a plastic bag, says author Jon Krakauer. Photo courtesy of McCandless family hide caption

itoggle caption Photo courtesy of McCandless family

Health worker Jackie Carnegie delivers a rubella vaccine in Colorado in 1972. Ira Gay Sealy/Denver Post via Getty Images hide caption

itoggle caption Ira Gay Sealy/Denver Post via Getty Images

St. Agnes Hospital in Baltimore is one of the 131 hospitals run by Ascension Health. It's a not-for-profit, Catholic health care system that treats many low-income patients. St. Agnes Hospital hide caption

itoggle caption St. Agnes Hospital

Rod-shaped specimens of Yersinia pestis, the bacterial cause of plague, find a happy home here in the foregut of a flea. Fleas can transmit the infection to animals and people, who can get pneumonic plague and transmit the infection through a cough or kiss. Science Source hide caption

itoggle caption Science Source

This image of a "red spot" on Mercury, which is thought to be the result of a volcanic explosion, was sent to Earth by the Messenger probe in 2011. NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington hide caption

itoggle caption NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Dr. George Papanicolaou discovered that it was possible to detect cancer by inspecting cervical cells. The Pap smear, the cervical cancer screening test, is named after him. American Cancer Society/AP hide caption

itoggle caption American Cancer Society/AP

An artist's rendition of the HD 7924 planetary system — just 54 light-years away from Earth — shows newly discovered exoplanets c and d, which join Planet b. Karen Termaura, BJ Fulton/UH IfA hide caption

itoggle caption Karen Termaura, BJ Fulton/UH IfA

Florida state Senate president Andy Gardiner, R-Orlando, was applauded by his fellow senators Tuesday, after expressing his disappointment with the Florida House for ending its session three days early, instead of working through the budget clash. Steve Cannon/AP hide caption

itoggle caption Steve Cannon/AP