Time is indeed of the essence in China. Today, there's still only one time zone for the entire country: Beijing Time, and time-telling as a means of enforcing unity has a long history in the Middle Kingdom.

One only need visit the Drum Tower and Bell Tower in Beijing for a vivid material example of the key role of time-keeping in past dynasties, stretching all the way back to the Han Dynasty (206 BC-220 AD), when the tradition of marking the hours with bells and drums within walled cities began.

Beijing's towers are, of course, the biggest in China (though Xi'an's Drum and Bell Towers may be more famous). The original wooden tower constructed on the site was completed in 1272 under the Mongol Yuan Dynasty. The tower we see today show the scars of history, having been damaged, destroyed and rebuilt a number of times over the years, with the historic drums on display today reputedly bearing scars from the 1900 Boxer Rebellion and the Japanese occupation of the city during World War II. Many other drums on view are reproductions.

Constructed on a four-meter-high base on the capital's ancient north-south axis, the Drum Tower rises 47 meters and stars a huge 1.5 meter-diameter drum known as gengu geng, the Night Watchman's Drum. There is also information on traditional Chinese time divisions and time-keeping methods, including an ancient water clock.

With the fall of the Qing in 1912, the towers ceased to mark time, though the Bell Tower's bell is now rung on occasion and drums are regularly struck 108 times to sound out Chinese tradition. Both massive time-pieces are open to the public.

Climbing the narrow and steep stairs as they wind their way upward through the stony bulk of the tower can induce a touch of claustrophobia in some, but the wide-open vista of the city one is rewarded with upon reaching the top more than makes up for it, especially on blue-sky days.