(CNN)A visit to Pingyao, in Shanxi province, feels like walking through a time capsule.
The 2,700-year-old city was once the renowned banking capital of China, as important in the latter part of the Qing dynasty (1644 to 1912) as Wall Street is in the United States today.
While its financial power has faded, Pingyao’s impressive architecture from that heady period, and before — including its 3.7 mile-long (6 kilometers) city wall — has remained remarkably intact.
In fact, Pingyao, which became a UNESCO World Heritage Site in 1997, still has some 4,000 traditional Chinese courtyard homes, dating as far back as the Ming dynasty (1368 to 1644).
“There are very few courtyard homes remaining in China,” says Kuanghan Li, director of the China Heritage Program at the non-profit Global Heritage Fund.
An innovative program is now helping to restore these properties to their former glory.
What is a courtyard house?