Archeologists have uncovered an intact drainage system dating back 2,000 years in Xi'an, the capital of northwest China's Shaanxi Province. The discovery sheds new light on the city's construction back in the Han Dynasty.

　　The drainage system was unearthed as archeologists excavated the relic site of Zhicheng Gate in suburban Xi'an. It's believed to be part of the ancient city of Chang'an, the Han Dynasty capital two thousand years ago.

　　Two groups of drainage tunnels built in different periods have been found. Experts say the tunnels built in the Xi'han Dynasty are the most intact of those found in Shaanxi Province.　

　　Liu Zhendong, archeologist, said, "Chang'an city back then had got a rather sound drainage system. From a palace to a larger project to the whole city, the system had been functioning well. "

　　As the excavation of the Zhicheng Gate progresses, the original appearance of the gate is gradually unveiled. A museum will be built at the relic site after the excavation is complete.