The moon almost blocks the sun before a total solar eclipse.
Americans from coast to coast donned protective glasses and gazed in awe at the first total solar eclipse to cross the nation since 1918.
Spectators marvel at the total eclipse in the football stadium at Southern Illinois University.
The total solar eclipse carved a narrow "path of totality" from coast to coast and Carbondale and Hopkinsville, Kentucky, were darkest for the longest, at 2 minutes, 38 seconds.
Depoe Bay, Oregon
The moon blots out the sun during a total solar eclipse.
Hilton Head, South Carolina
Brothers Chris and Gabe Fabiano watch the eclipse on the beach.
Over the Pacific Ocean
The sun is obscured by the moon during a solar eclipse as seen from an Alaska Airlines commercial jet at 40,000 feet.
Depoe Bay, Oregon
Spectators watch the skies darken during the total solar eclipse.
People view the solar eclipse at the "Top of the Rock" observatory at Rockefeller Center. Around 72 percent of the sun was covered by the moon during the peak time of the partial eclipse in New York City.
International Space Station
The moon casts a shadow as seen from 250 miles above Earth. As millions of people across the United States experienced a total eclipse, only six people witnessed the umbra, or moon's shadow, from space. The space station crossed the path of the eclipse three times as it orbited Earth.
The White House
President Donald Trump watches the solar eclipse with first lady Melania Trump and son Barron from the Truman Balcony.
The nation's capital experienced a partial solar eclipse, with 82% of the sun bocked by the moon.
A composite image of five pictures shows the progression of the total solar eclipse.
People watch the start of the solar eclipse at Big Summit Prairie ranch in Oregon's Ochoco National Forest.
Spectators watch the skies.
Students watch the solar eclipse during a viewing party sponsored by the University of California-Irvine Department of Physics and Astronomy.
A solar flare erupts from the sun as it emerges from a total eclipse.
The White House
Members of the media watch the solar eclipse.
The partially-eclipsed sun casts shadows on a sidewalk at Oregon State University.
Myrtle Beach, South Carolina
Day turns to evening as darkness descends on the beach in front of the Marriott Resort and Spa at Grande Dunes during the solar eclipse. Myrtle Beach was supposed to see 99-percent coverage of the sun by the moon but heavy cloud cover prevented people from seeing the moment of peak eclipse.
Northern Cascades National Park, Washington
The International Space Station, with a crew of six, transits the sun at roughly five miles per second during a partial solar eclipse in a composite image made from four frames.
Alto Pass, Illinois
Joe Roth, left, and Scott Foster from the Chicago area are silhouetted as they prepare telescopes and cameras to observe the eclipse at the base of the Bald Knob Cross of Peace.
Valle de Santa Ines, Spain
Figures are silhouetted on a hillside during a partial solar eclipse just before the sun drops below the horizon.
Cheerleaders try out eclipse glasses that they were distributed to visitors to Saluki Stadium on the campus of Southern Illinois University.
Mike Newchurch, left, professor of atmospheric chemistry at the University of Alabama in Huntsville, and graduate student Paula Tucker prepare a weather balloon before releasing it to perform research during the solar eclipse on the Orchard Dale historical farm near Hopkinsville.
A NASA-sponsored initiative that has teams from more than 50 universities and high schools from 30 states deploying a series of camera-equipped weather balloons from points stretching from Oregon to South Carolina.
C.D. Olsen adjusts the image on his replica of a kew photoheliograph camera as it displays an image of the sun on the campus of Southern Illinois University before the start of a total solar eclipse.
Hank Fridell, of Custer, South Dakota, test out his eclipse glasses and his foil hat while visiting Carhenge. The site, which mimics England's Stonehenge, was on the path of totality and was preparing for a deluge of visitors.
A boat sails under a partial solar eclipse in northwestern Spain on Aug. 21, 2017.