History

President Obama has said he will veto the Keystone XL pipeline project, which passed in the Senate on Wednesday. Historically, political scientists say, 90 percent of veto threats are issued behind the scenes, but Obama has issued nine veto threats so far — in public. Mandel Ngan/AFP/Getty Images hide caption

Nobel Prize-winning physicist Charles Townes was single-minded about a lot of things, colleagues say. And also a very nice guy. Julian Wasser/The LIFE Images Collection/Getty hide caption

Laura Ingalls Wilder entertained generations of children with her Little House series, which was loosely based on her family's pioneering life. Her memoir, Pioneer Girl, was published in 2014. South Dakota State Historical Society hide caption

Jack Mandelbaum, a Holocaust survivor from the Polish city of Gdynia, poses in front of a photograph showing him as a youth. Tobias Schwarz/AFP/Getty Images hide caption

Julie Byard, head of a Detroit nursery, tells children stories and sings them songs prior to their afternoon nap in 1942. AP hide caption

Frank Sinatra captured by photographer William "PoPsie" Randolph during a 1943 concert. Author Ben Yagoda points to Sinatra as one of the interpreters who helped revive the Great American Songbook. William "PoPsie" Randolph/Courtesy of Riverhead hide caption

The ancient scrolls look and feel more like blocks of charcoal. A new technique gives a peek inside. Salvatore Laporta/AP hide caption