The stethoscope seems so simple — a 19th century tool for listening more closely to the human heart or lungs. It also sparked a culture of listening that is transforming the way scientists learn.
President Obama is the first sitting president to visit a federal prison.
Kevin Lamarque/Landov
hide caption
A young man peers out a window in a holding cell after arriving at the intake unit at Alameda County Juvenile Hall.
Brett Myers/Youth Radio
hide caption
Afaf Shini, a host on the Palestine 48 TV channel, holds a reading card with the satellite channel's logo during a morning broadcast in Ramallah in July. Israel shut down operations just days after the launch.
Nasser Nasser/AP
hide caption
