The story of ancient Hefei is a tale of two cities - one raised for war, another for peace, one with a history long interred in ruins, while the legacy of the other continues until today.

While Grand Castle - an outpost built 1,780 years ago to defend the nearby Cao Wei Kingdom (AD 220-265) city of Sanhe - was not destroyed by foreign attacks, it was the very lack of peacetime assaults and the consequent neglect that eventually brought down its walls.

Rather than repelling invading troops, it today attracts armies of tourists who besiege the Park of the Three Kingdoms Ruins, the 35-hectare preservation site built around the ancient bulwark's remains in Anhui's provincial capital.

Grand Castle was constructed near Wei's border with the state of Wu during the Three Kingdoms (AD 220-280) period - a time when a trio of dynasties was deadlocked in a bloody stalemate in their quests to unite and rule China.

The outpost not only withstood 11 attacks from Wu soldiers between AD 230 and 268 but also did so while chalking up huge enemy body counts.

Grand Castle's 6,000 guards defeated more than 100,000 Wu soldiers in AD 234, and 7,000 guards vanquished another 100,000, 19 years later.

After general Sima Yan wrested the Wei throne from the Cao lineage and defeated the other two countries to unite China, the bulwark - no longer needed, as the border it protected no longer existed - was gradually ground into ruins by the sands of time.

Visitors today zip among the remnants in electric carts shaped like vintage cars adorned with Mercedes-Benz hood ornaments. They see the foundations of 18 bases of the 15-meter-high clay city wall, reconstructions of its three gates, and the foundations of a weapons-manufacturing plant and a barrack.

Traditional stone work pattern in Sanhe's Old Supermarket, one of the former centers of trade and commerce in Hefei's ancient city. (By Jonah m. Kessel)