The deserted Diantou village looks like a cluster of tumbledown caves.
And few would have thought it was anything more if not for the efforts of former resident Li Guihu, who has long believed in the potential of what is actually a 1,700-year-old castle - a discovery of great surprise to the former inhabitants, who vacated the settlement for cozier accommodations about two decades ago.
When two history professors ascertained the truth about the history of the hamlet in Shanxi's provincial capital Taiyuan, Li immediately saw its value as a place of archeological value and tourism interest.
Located 2.5 km from ancient Jinyang's city ruins, Diantou pocks the northern base of Mengshan Mountain. The mouths of the subterranean homes open toward Longshan Mountain across a creek. The foot of Longshan is traced by what was once the only road leading to the ancient Loufan kingdom.
The caves were likely part of a fortress defending that strategic route. It's said that the founder of the Tang Dynasty (AD 618-907), Emperor Li Yuan, stationed his army here. This is also believed to be the starting point for his expeditions to overthrow the Sui Dynasty (AD 581-618) and other warlords.
Strolling among the caves, visitors come to realize the uniqueness of the structures. Passageways with doors connect more than 400 caverns, making the complex like a beehive in outward appearance and an anthill in internal structure.
Even though many of the tunnels are now blocked, it's easy to get lost inside. Guides lead guests through the maze without ever returning to a previously traversed route.
Such a labyrinth would have been difficult to besiege. Many openings are so small that only one person could squeeze through at a time, enabling them to be defended by a single soldier.
A secret passageway contains a spring - a water source for an army hunkering down for a long siege. And the caves are replete with mills enabling those inside to grind flour without leaving.
The third story of the complex offers bird's-eye views of the road across the stream, which is within arrows' reach.
It's unknown whether Diantou's tiny Buddhist temple was built by villagers after Song Dynasty Emperor Taizong razed nearby Jinyang in AD 979 or has been there since the stronghold's construction.
The holy spot enabled troops to worship any time they wished to express gratitude for Buddha's protection. And the temple's location at the terminus of the passageways literally creates a light at the end of the tunnel.
The caves pocking the mountainside's highest reaches are peculiar. These feature a massive round stone disc rolled from inside to seal out invaders at the entrance, and many secret passageways inside. Many of these hidden tunnels remain unexplored, and some suspect they lead to nearby Mengshan.
It's said there are caves inside the mountain that are sealed shut by ice blocks that haven't melted for hundreds of years. This might be connected to the source of the castle's spring. And building the structures near Mengshan may have ensured access to water if the fortress was attacked.
A narrow lane, big enough for three people to walk along side-by-side, stretches westward from the temple.
The pathway leads to a small square and a small stage with a crumbling roof and enough space for hundreds of spectators. Just north of the stage is a multi-layered stone shelf built for placing candles during ceremonies.
The shelf faces the slender trail leading to its eastern end, enabling all who traverse it to see the flickering flames.
This road is said to be the route along which Emperor Taizong led his troupes to ravage Jinyang.
Across the stream, which is heavily polluted by coke, the sounds of traffic serve as a reminder of the need to protect this ancient barracks.
Because, while Diantou has revealed many secrets of Jinyang's rise and fall, the fortress still protects many of them, which we have yet to discover.
Hou Jinxiang contributed to the story