Angkor, which means Holy City, was built by the Khmer empire between the 9th and 15th centuries Photo: ALAMY
It is one of the greatest archaeological treasures in the world – a 1,000 year
old city that once covered an area the size of London.
Yet how the builders of Angkor in Cambodia dragged the enormous 1.6 ton blocks
of stone used to construct the grand temples and monuments that litter the
city from distant quarries has baffled historians for decades.
Now new research using satellite images has revealed that the Khmer rulers dug
a 21 mile long canal across their kingdom to transport the sandstone blocks
from a mountainside quarry to their capital city.
The discovery may help to explain how the enormous temple of Angkor Wat, built
using five million tons of sandstone, was constructed in just 35 years
despite estimates that it should have taken several hundred using the
technology available at the time.
It was originally thought that each stone block was dragged on a tortuous 55
mile journey that could have taken several days over land, along rivers and
across a lake to Angkor.
Instead, archaeologists have found the remains of a network of canals that
cuts across the country, occasionally merging with short stretches of river,
and would have allowed the stone to be floated downstream on rafts with
little effort in a journey they estimate would have taken just 10 hours.
Professor Etsuo Uchida, from the department of resources and engineering at
Waseda University in Tokyo, said: "These canals were constructed
specifically for the transportation of sandstone blocks.
"Compared to the previous transportation route proposed, this new route
saves so much time. This canal is almost the shortest route and makes us
consider that the Khmer people conducted the construction of the temples
systematically and very effectively."
Professor Uchida and his colleagues found traces of the canals while looking
at satellite images of the area around Angkor ruins, which revealed
distinctive straight lines where the banks from the waterways cut across the
landscape.
When the researchers visited the region they found some canal remnants still
containing water, while others had disappeared beneath roads or had dried up
and become overgrown.
They also discovered large sandstone blocks at various points along the route
where they had either fallen off rafts or been taken ashore for some reason.
The network of canals runs from an area of quarries at the foot of Mount
Kulen, where the sandstone was found to match that used to build the temples
in Angkor. Archaeologists also found a further 50 new quarries along the
route of the canal where stone had been dug out.
Angkor, which means Holy City, was built by the Khmer empire between the 9th
and 15th centuries. It is thought to have been the largest pre-industrial
city in the world and sprawled over 390 square miles.
It was abandoned in mysterious circumstances in the 15th century and much of
the city was gradually reclaimed by the jungle before more recently becoming
a major tourist attraction and a World Heritage Site.
A series of elaborately carved temples formed the core of the city, the most
famous of which was Angkor Wat, the largest Hindu temple complex in the
world, built by Kind Suryavarman II in the early 12th century.
The carefully carved stone blocks used to construct the temple and the
surrounding monuments were up to three feet across in some places and
weighed around 1.6 tons.
Experts had previously believed these blocks were dragged over land from Mount
Kulen to a river that carried them to the Tonle Sap Lake, where they were
sailed up to Siem Reap River and then pulled upstream to the construction
site in Angkor.
Professor Uchida said his findings had found a far more efficient route that
would have drastically sped up the construction process.
He said: "I estimate that the construction of the canals took only a few
years. They probably used boats or rafts to carry the blocks.
"Because it is not necessary to go upstream in the Siem Reap River, it
seems that sandstone blocks were transported efficiently by this canal route."
