Sunrise in Yosemite National Park.
Photo by GabPRR, used under...
Greyhound managed transportation options on the grounds of the 1939 New York World's Fair.
New York City's daily carbon dioxide emissions visualized. Each sphere represents a ton of carbon.
Wolves in Yellowstone.
"Now, here, you see, it takes all of the running you can do to keep in the same place.
Shirlington Library and its adjoining plaza in Arlington, Virginia, after the area's successful redevelopment.