Earlier this week, protesters marched for Freddie Gray through downtown Baltimore. Gray died from spinal injuries about a week after he was arrested and transported in a police van. A larger protest is planned for Saturday afternoon. Patrick Semansky/AP hide caption

itoggle caption Patrick Semansky/AP

A reporter stands outside the front door of a house registered to a trading company operated by Navinder Singh Sarao in Hounslow, west of London. on April 22, 2015. Sarao was arrested in connection with the Wall Street flash crash of 2010. Adrian Dennis/AFP/Getty Images hide caption

itoggle caption Adrian Dennis/AFP/Getty Images

"Question Bridge: Black Males" attempts to represent black male identity in America via a video question-and-answer exchange. At top center is Jesse Williams, the project's executive producer. Question Bridge: Black Males hide caption

itoggle caption Question Bridge: Black Males

The Hooker 100-inch reflecting telescope at the Mount Wilson Observatory, just outside Los Angeles. Edwin Hubble's chair, on an elevating platform, is visible at left. A view from this scope first told Hubble our galaxy isn't the only one. Courtesy of The Observatories of the Carnegie Institution for Science Collection at the Huntington Library, San Marino, Calif. hide caption

itoggle caption Courtesy of The Observatories of the Carnegie Institution for Science Collection at the Huntington Library, San Marino, Calif.

The National Guard Bureau commissioned this painting, "Indiana Rangers: The Army Guard in Vietnam," as part of its series of paintings depicting significant moments in Guard history. It represents members of the Company D, 151st Infantry division — one of a few Guard units deployed to Vietnam — on duty in the jungle Mort Kunstler/National Guard Bureau hide caption

itoggle caption Mort Kunstler/National Guard Bureau