The Department of Homeland Security (DHS) has issued new guidelines prohibiting photos of clocks, watches, and other timepieces because of concern that these photos will provide aid to terrorist organizations seeking to create clocks that look like bombs. This new regulations prohibits taking, editing, or storing photographs that provide information on timekeeping. Google is reportedly working to remove all photos of clocks and watches from its image database. When asked about other timepieces, DHS Secretary John Irving indicated that photos of sundials and hourglasses are also prohibited since they can be used to conceal explosive devices.
Note added September 26, 2015: This article is based on 14-year old Ahmed Mohamed who was arrested in Irving, Texas for building a clock that his teacher thought was a bomb. For more details see Muslim teen Ahmed Mohamed creates clock, shows teachers, gets arrested.