ZIGONG, China, a thriving industrial centre, has long been an important source of salt , tapped for thousands of years from artesian basins below the city. In the fourth century the Sichuanese were sinking three-hundred-metre-deep boreholes here using bamboo fibre cables attached to massive stone bits, later replaced by more effective two-piece percussion drills. By the 1600s, bamboo buckets were drawing brine from wells bored almost a kilometre beneath Zigong, centuries before European technology (which borrowed Chinese techniques) could reach this deep. Natural gas , a byproduct of drilling, was used from the second century to boil brine in evaporation tanks, and now powers city buses - look for the huge, floppy black rubber gas bags on their roofs.

Start off a city tour at the splendid Qing-era Xiqin Guildhall on central Jiefang Lu, now an absorbing salt Museum (8.30am-5pm; ¥5), full of photos and mining relics - including drill bits which look like part of a medieval torturer's armoury. One of the best things here is the building itself, whose extravagantly curled roof corners, flagstone-and-beam halls, and finely carved woodwork were renovated in 1872 by master craftsman Yang Xuesan. Several other contemporary structures survive in Zigong, including two marvellous tea houses where you can gossip, lounge or play cards with locals surrounded by dated furnishings: the unmissableWangye Miao, which sits high over the river near the Shawan Binguan on Binjiang Lu; and a former theatre with a beautifully carved stone gateway at the junction of Jiefang Lu and Zhonghua Lu.

Bus #3 to Dashanpu (¥0.5) from opposite the Shawan Binguan on Binjiang Lu heads 15km northeast into Zigong's suburbs. Along the way you pass Xinhai Well (¥1), the deepest ever drilled using traditional methods at a fraction over 1000m. In use until 1966, the twenty-metre-high wooden tripod minehead still towers over the site, and you can look at the rusted evaporation tanks (gas now boils the caretaker's kettle), bamboo-fibre cables, excellent stone engravings on the wall detailing the well's development (much using buffalo power), and the tiny well shaft itself, corked and barely 20cm across. Stay on the bus and it's about 45 minutes from Binjiang Lu to the Dashanpu terminus, from where you'll have to walk the last 500m to Zigong's dinosaur Museum (8.30am-5pm; ¥20), built over the site of excavations carried out during the 1980s with the help of the British Museum. Near-perfect skeletal remains of dozens of Jurassic fish, amphibians, and dinosaurs - including monumental thighbones, and Sichuan's own Yangchuanosaurus , a lightweight velociraptor - have been left partially excavated in situ, while others have been fully assembled for easy viewing; poor lighting and captions are minor quibbles.