Humans have an elegant and intricate system of internal processes that help our bodies keep time, with exposure to sunlight, caffeine and meal timing all playing a role. But that doesn't account for "precision waking." Sarah Mosquera/NPR hide caption
Far from the Earth, time gets extremely weird. Black holes can cause it to stretch and even break down entirely. NASA/JPL-Caltech hide caption
Europe is struggling to keep up with the times after a political dispute resulted in electric clocks running six minutes behind. Paul Bricknell/Getty Images/Dorling Kindersley hide caption
Ramos is a remotely deactivated alarm clock that forces the user to get out of bed for the alarm to turn off. Ramos hide caption