While flooding was frequent at Wiang Kum Kam, archaeologists suspect there was a “super flood” that caused the southern site to be buried by sediment and abandoned altogether in the 16th century.
It was not until the 1980s that efforts to uncover the ruins were made by the Thai government’s Fine Arts Department.
Because of its subterranean nature, Wiang Kum Kam has been dubbed Thailand’s Lost Kingdom, Thailand’s Forgotten Kingdom and The Underground Empire.
The ancient city does not rank high on most visitors’ “must-see” lists, but this makes it a refreshing and rewarding experience for anyone curious about Lanna’s illustrious past and Chiang Mai’s laid-back present.
It is best to begin a tour of Wiang Kum Kam at the information centre, just east of the Ping River on the middle ring road, where relics from the site such as stucco carvings provide a tantalising introduction.
From here, hire a pony and carriage (300 baht; US$8.30) that will take you for about an hour on a winding route to look at nine of the best-restored temples. Alternatively, you can ride around the site on a bicycle or motorbike, although it is easy to get lost in the maze of lanes.
Most of the temples that have been uncovered (to date, around 40) lie within a square kilometre that is hemmed in by two busy Chiang Mai ring roads.
Nearly all consist of little more than foundations of a viharn (assembly hall) and a brick stupa, so it can get a bit repetitive if you try to take them all in.
The first stop on our suggested pony and carriage tour is Wat Ku Pa Dom, where the remains of an assembly hall, ordination hall, stupa, well and boundary wall can be seen sitting a couple of metres below the surrounding land.
An angled retaining wall here – as with those at most other temples along the way – is designed to prevent further damage from flooding.
The next stop is Wat Chang Kham, a modern temple built on the site of an older place of worship, Wat Kamthom, which is where excavations of the ancient city began, in 1984.
All that remains of Wat Kamthom is the base of the viharn and stupa, but several elements of Wat Chang Kham are of interest, including a shrine to King Mangrai, a delightfully decorated scripture library, several statues of mythical creatures and a bodhi tree supported by colourful poles.
Keep an eye open for an unusual cannonball tree, with bright pink blossoms and cannonball-sized fruit, near the back entrance.
The most complete of the ruins are Wat E-Kang and Wat Pupia, both of which feature a stupa and the remains of several buildings, although once again the retaining walls demonstrate that the temples are well below ground level.
Wat Pupia is the only temple with some remaining elements of stucco carvings, near the top of the stupa.
Stories about the excavations give an idea of how exciting the past 40 years have been.
Apparently Wat Nanchang, which had been built in two distinct periods, was buried beneath a longan orchard. The root system of longans is shallow, and when one tree toppled over under the weight of its fruit in 2002, it revealed signs of what turned out to be a huge underground temple.
The last temple on this tour is Wat Chedi Liam, which appears to be a modern structure, although the square stupa here, with five receding levels and Buddha images in niches, has been rebuilt many times through the centuries since it was first erected by King Mangrai, in memory of his wife.
As at Wat Chang Kham, it is worth wandering around the tranquil site with its assembly hall, ordination hall and spirit houses, before picking up a souvenir at one of the stalls and clip-clopping back to base with a tired pony and driver.