With the possibility of a strike on Syrian targets, U.S. firms are trying to protect themselves from cyberattacks that may follow. iStockphoto.com hide caption

itoggle caption iStockphoto.com

A little chilly for camping: Ice-penetrating radar revealed a mega-canyon below the Greenland ice sheet, extending for more than 460 miles. Courtesy of J. Bamber/University of Bristol hide caption

itoggle caption Courtesy of J. Bamber/University of Bristol

American folk singer and activist Pete Seeger (left) adopted and helped popularize "We Shall Overcome" by teaching the song at rallies and protests. Here he sings with activists in Greenwood, Miss., in 1963. Adger Cowans/Getty Images hide caption

itoggle caption Adger Cowans/Getty Images

Flames burn near the Tuolumne Family Camp near Groveland, Calif., on Sunday. Noah Berger/EPA/Landov hide caption

itoggle caption Noah Berger/EPA/Landov

The headquarters of Menlo Innovations, a software design firm in Ann Arbor, Mich. At Menlo, there are no cubicles, few walls and no offices. Elise Hu/NPR hide caption

itoggle caption Elise Hu/NPR

Demonstrators on Saturday in Washington, D.C., commemorate the 50th anniversary of the March on Washington for Jobs and Freedom. Kevin Lamarque/Reuters/Landov hide caption

itoggle caption Kevin Lamarque/Reuters/Landov

This may look like a mad scientist's garage sale, but it's actually the most precise clock ever built. Jim Burrus/NIST hide caption

itoggle caption Jim Burrus/NIST

A puffin prepares to land with a bill full of fish on Eastern Egg Rock, off the Maine coast in July. Last year young puffins died at an alarming rate from starvation because of a shortage of herring. Robert F. Bukaty/AP hide caption

itoggle caption Robert F. Bukaty/AP

Seattle law enforcement's mellow attitude toward pot was on display at this year's annual Hempfest, where the cops were at the gate — handing out bags of Doritos. Martin Kaste/NPR hide caption

itoggle caption Martin Kaste/NPR

From left, Garrett Berntsen, Jennifer Majer and William Shields compare notes at The Johns Hopkins University School of Advanced International Studies in Washington, D.C. Twenty-somethings have new choices under Obamacare. Heather Rousseau/NPR hide caption

itoggle caption Heather Rousseau/NPR

Ushio Shinohara is best known for his "boxing paintings" — performance pieces often created for an audience, in which he strikes at his canvases with gloves dipped in pigments — and for his fanciful, brightly colored sculptures of motorcycles adorned with all manner of extras. Radius/TWC hide caption

itoggle caption Radius/TWC

Opponents of North Carolina's new voter ID legislation wear tape over their mouths while sitting in the gallery of the House chamber of the North Carolina General Assembly in Raleigh, N.C., on April 24, where lawmakers debated new voter laws. On Monday, Gov. Pat McCrory signed a new law that requires a state-approved photo ID to vote and cuts early-voting opportunities. Gerry Broome/AP hide caption

itoggle caption Gerry Broome/AP

The olinguito is the first carnivore species to be discovered in the Western Hemisphere in 35 years. Courtesy of Mark Gurney hide caption

itoggle caption Courtesy of Mark Gurney