Big time in Mecca

In Mecca, Saudi Arabia, one minute after midnight on Aug. 11, 2010, the beginning of the holy Islamic month of Ramadan was marked by the start of the world’s largest clock. The Mecca Clock sits atop the 2,000-foot-tall tower five of the seven-tower Abraj Al Bait complex, scheduled to be completed in fall 2011.

Each of the clock’s four faces is 151 feet in diameter and will be covered with millions of pieces of glass mosaic. Each side bears the words “Allah is greatest,” and 21,000 LED lights atop the clock will flash five times a day for the call to prayer. At press time, only one face was functional, undergoing a three-month test run.