U.S. Park Police officers arrest demonstrators in front of the While House on Thursday. They were protesting against a proposed 1,700-mile-long pipeline that would carry oil from the tar sands in Alberta, Canada, to the U.S. Gulf Coast.
President Obama speaks in the Rose Garden on Wednesday, flanked by U.S. Chamber of Commerce Chief Operating Officer David Chavern (left) and AFL-CIO President Richard Trumka (right). Business groups and unions are just two of the groups Obama will try to please with his jobs plan next week.
A lab technician prepares blood samples from volunteers for viral genotyping at a government-run health center in Bagamoyo, Tanzania, in 2009. Tanzania is currently hosting the final stages of a human trial of a pioneering vaccine against malaria. The vaccine is one of many medical innovations to emerge from Walter Reed over the decades.
Tony Karumba/AFP/Getty Images