Chinese people often say cang hai sang tian or "the ocean changes to land and the land becomes ocean" to indicate how time brings great changes to the world.
Beneath the cities of Huaibei (淮北) and Suzhou (宿州) in northern Anhui Province lies a segment of the vast waterway, the Grand Canal of China. After the unused canal silted up, the area became a modern granary of wheat and production area of vegetables and fruit.
More recently, buildings, skyscrapers, factories, houses, parks and other urban structures have been built on top of the buried canal. The ocean, or water, indeed turned to land.
The ancient canal, once filled with passenger ships and cargo vessels carrying grain, silk and tea that were sold all over the world, is now buried dozens of meters under wide cement streets filled with passenger cars.
"Buried under this modern city is a whole sleeping canal system 1,000 to 1,500 years old, a lively historic underground," Han Sanhua, head of the Suzhou Municipal Cultural Heritage Bureau, tells Shanghai Daily at the office in Yongqiao District.
"This whole downtown area is called Yongqiao (qiao means bridge) District because there was once a bridge here above the canal," Han says.
The street, just five minutes' walk from his office, is basically on top of the ancient canal. The bridge, called Yong Bridge, is long gone, but the street is not entirely flat. It has got a bit of a bump that is left from the buried bridge.
Outside Suzhou is a local river that once was part of the canal. On one bank are villagers' red-brick houses, on the other side there's a small wooded hill.
Villagers say that in the rainy season the water can rise as high as the first row of trees on the hill and it's easy to catch lots of fish, simply by dragging a fish net in the water that's only around four meters deep.
This segment of the river, or stream, is 25 kilometers long, around 18 meters wide and 2 meters deep; on each side are two or three meters of river bottom.
At the first glance, this stretch of river bottom looks no different from other rivers in the area, except for a small archeological site. Shards of pottery can easily be dug by hand from the soft, silty river bed or wall of the site; it just takes a few minutes.
This 25km stretch is the only part of the ancient canal remaining above ground in Anhui Province. It is not wide or deep enough for traffic but villagers still use it to irrigate their wheat and vegetable fields.
Irrigation, along with transport and flood control, was one of the canal's functions when it was built in the Sui Dynasty (AD 581-619). It was expanded later in the Tang Dynasty (AD 618-907) and became known as the Sui-Tang Grand Canal.
About 180km of the 3,200km Grand Canal of China passed through the province, mainly through Huaibei and Suzhou cities. All but this section is buried.
It's very rare, especially in the north, to still have a part of the Sui-Tang Grand Canal above the ground. While most of the better-known Beijing-Hangzhou Canal, mainly dug in the Ming (1368-1644) and Qing (1644-1911) dynasties, are still above the ground and even in use, most of the Sui-Tang Grand Canal in Anhui and Henan provinces has been buried for more than 1,000 years, says Zhang Wei from the local Sixian County Grand Canal Bidding Office.
The Sui-Tang Grand Canal and Beijing-Hangzhou Grand Canal are both parts of the 3,200km Grand Canal of China, which will be submitted for recognition as a UNESCO World Heritage Site.
The Sui-Tang part was the first national systematic project that linked rivers, streams and lakes through a system of artificial canals around the country, creating one transport network.
The major destinations of the Sui-Tang Grand Canal were today's Xi'an in Shaanxi Province and Luoyang in Henan Province. The two cities served as capitals for different emperors during Sui and Tang dynasties.
So the canal turned westward to Anhui from Jiangsu Province to reach Henan and then turned back eastward from there, passing through Shandong to the north to reach Beijing. The extensions in Anhui and Henan provinces were deserted when Yuan Dynasty (1279-1368) authorities moved the capital to Beijing. The detour was no longer necessary. New canals were built to link Jiangsu and Shandong and other canals were redesigned in other areas to shorten the trip.
The new route that no longer went through Anhui or Henan was the Beijing-Hangzhou Grand Canal.
"People often talk about how the Grand Canal connected northern and southern China's economy, trade and culture, which is all correct and great. But it was also essentially a state-run transportation system, and one of the main purposes was to effectively disseminate court orders from the emperor to the most remote territories so orders were implemented efficiently," says Wang Hongwu, chief curator of Sui-Tang Grand Canal Museum in Huaibei.
An abundance of pottery was found in archeological sites in Suzhou and Huaibei, along with parts of ancient vessels and big polished round stones that were thrown by local villagers to attack boats. The canal in this area was narrow and shallow with many turns, making the boats close to river banks and easily attacked.
Even more evidence was discovered in Huaibei in 1999 in a major archeological dig in suburban Liuzi Village. The excavation was considered one of the 10 greatest archeological projects that year in China because it proved the exact route of the Sui-Tang Grand Canal.
Archeologists discovered a rectangular stone site they believed to be the remains of an ancient dock. This year, a similar stone was excavated on the other side of the ancient canal and archeologists suspect it may have been the foundation of a bridge.
Hundreds of pieces of delicate porcelain from the Tang and Song (960-1279) dynasties were found near eight vessels including a buried, 18-meter-long passenger vessel. Tons of pottery suggested how crowded and prosperous the canal was at this spot.
The archeological site is now closed and the artifacts, including pottery and parts of vessels, are displayed in Huaibei's Sui-Tang Grand Canal Museum, revealing a bit of the buried canal and history.
Archeological findings in the area are mostly from the Tang and Song dynasties, when the canal was at its peak, or the Han Dynasty (BC 206-AD 220). Hundreds of years of other dynasties in between are missing because this militarily strategic heartland area was often torn by war and natural disaster, such as the massive flooding and course changes of the Yellow and other rivers.
"The history in this region is almost defined by war," says Han from Suzhou's cultural bureau. "We have either a grand war or a natural disaster in the region every 100 years or so, so it often became a conflict frontline and a no man's land. It's not easy for archeologists to explore here. History was either destroyed in war or has been buried underground."
Ancient books often describe Suzhou's Yong Bridge as strategically significant because it's in the area between northern and southern China, and also because occupying this bridge is critical for those seeking to control Bianshui, the part of the Grand Canal that connected the water networks in the region. Controlling the regional water system made it possible to control enemies' lifeline for supplies.
Due to its military importance, the area has been fought over by forces from all adjacent areas. Since the early Zhou Dynasty (1046-256 BC), the place has always been a border between different states or empires and filled with battles.
The years between the Han and Tang dynasties were especially turbulent with uprisings and kingdoms rising and falling within years.
The canal brought prosperity to the war-torn area and this lasted 300 to 500 years until the late Song Dynasty, chief curator Wang explains. At that time the emperor and the government in Henan's Kaifeng were defeated by their northern enemies and retreated south of the Huai River to Hangzhou. The region again became a frontline.
It was around that time in the late Song Dynasty, after many battles, the canal system was gradually abandoned and finally buried by heavy silt and great geological changes in the area.
When the Yuan Dynasty took over and moved capital to Beijing, the canal in this region was long gone.
"And the progress of 300 to 500 years brought by the canal was also quickly gone," Wang adds.
Among the grand stages of war that changed Chinese history, many were in this region. In 202 BC, Emperor Gao, founder of the Han Dynasty, defeated his last and strongest enemy here, forcing him to commit suicide.
In the late Song Dynasty, generals famously fought continuously to hold the border that was crucial for the dying dynasty, with its capital moved from Kaifeng to Hangzhou, to survive for another 100 years.
In late 1948 and early 1949, PLA soldiers and the Kuomintang army fought for two months in this area, until the Communists finally defeated the KMT in one of its most strategically important victories.
Even today, the area is where four provinces meet - Anhui, Henan, Jiangsu and Shandong - and its residents share more similarities to and customs with northern Chinese than those in southern areas.
Northern Anhui Province, about three hours from Shanghai by bullet train, is very different from the southern part of the province, which has gradually become a popular choice for companies expanding in the Yangtze River Delta Region. Southern Anhui, quite similar to Zhejiang and Jiangsu Provinces, is filled with small local factories and industrial zones that boost regional economic development.
The northern area is still largely agricultural and consists of vast rice paddies. It lags behind economically, so local governments have started to build large industrial zones and woo companies.