navigation
Young European eels (Anguilla anguilla) are called "glass eels" at that stage because they're transparent except for a dark spine down the middle. Philippe Garguil/Science Source hide caption
Navigation aboard the guided-missile destroyer USS Stout is done by computer, as is the case on many other ships. The U.S. Navy now wants more of its officers proficient in celestial navigation. Amanda Gray/U.S. Navy hide caption
A couple from Namibia's Twe tribe outside their home. Tribe members took part in a study that examined the relationship between navigation skills and mating success. Layne Vashro/University of Utah hide caption
Some Uber drivers and passengers complain that the app's built-in navigation doesn't give its drivers the best directions. Adam Berry/Getty Images hide caption
Which way do we turn here? A passageway in London's Soho neighborhood. ceajaegirl/Flickr hide caption