Previous experience with dengue outbreaks in Puerto Rico has shown that even small amounts of standing water — as in the vases of cemeteries — can serve as breeding areas for the mosquitoes that carry dengue and Zika.
Pan American Health Organization/Flickr
Fueled by low gas prices and a stronger economy, Americans drove a record 3.15 trillion vehicle miles in 2015. But the additional driving may lead to more pollution and traffic gridlock.
Zoran Milich/Getty Images
The half-naked hatchetfish,shown here munching on a shrimp, is just one of many billions of mesopelagic ocean fish that migrate up and down the water column each day to hunt food and avoid predators.
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