A sign hangs in the window of an information booth at the Lincoln Memorial in December 1995, announcing the temporary closure of the attraction due to the government shutdown. Mark Wilson/AP hide caption

itoggle caption Mark Wilson/AP

Carnegie Mellon's autonomous car, developed with General Motors, is by all appearances a normal Cadillac SRX crossover — except for the big red button in the middle of the dashboard. In an emergency, the button allows the car to be switched immediately back to standard driving mode. GM-Carnegie Mellon Autonomous Driving Collaborative Research Lab hide caption

itoggle caption GM-Carnegie Mellon Autonomous Driving Collaborative Research Lab

U.S. Postal Service letter carrier Jamesa Euler delivers mail in the rain in Atlanta in February. David Goldman/AP hide caption

itoggle caption David Goldman/AP

President Obama has nominated John Koskinen to be commissioner of the Internal Revenue Service. Ron Edmonds/AP hide caption

itoggle caption Ron Edmonds/AP