Visit Cambodia's number one tourist attraction, Angkor Wat, with the average tour guide and you'll probably leave the UNESCO World Heritage Site with your head swimming in dates, dimensions and unpronounceable names of kings.
You might also get the impression, as I did when I first visited two years ago, that the magnificent temple complex you scrambled around in sweltering heat is confined within its sturdy walls and scenic moat, and the city ended there.
Turns out that's not the case.
A new report released by the U.S.-based National Academy of Sciences (NAS) highlighting the results of an April 2012 airborne laser survey -- the first of its kind in Asia, covering 370 square kilometers of northwest Cambodia's Khmer Empire archaeological sites -- has revealed a much grander Angkor landscape, one without parallel in the pre-industrial world.
Even more sensational, the June announcement of the findings confirmed the existence of a huge medieval city buried beneath impenetrable jungle on a remote mountain.
Re-writing Cambodia's history books
Angkor was the capital of the Khmer Empire, which was founded in 802 AD on Mount Kulen when Jayavarman II was declared universal monarch.
These days the most popular Angkor sites for tourists are Angkor Thom, which is home to Bayon and its massive carved smiling faces; magnificent Angkor Wat; and smaller temples such as Ta Prohm, Preah Khan, Pre Rup and Ta Nei.
But the precise data gathered by LiDAR, a remote sensing laser instrument, reveals that Angkor was actually a monumental, formally planned and low-density mega-city.
Less visited ruins further afield, such as enchanting Beng Mealea, 52 kilometers from Siem Reap and sprawling Koh Ker, some 120 kilometers away, were actually satellite cities within Angkor's colossal urban network.
Phnom Kulen, or Mount Kulen, meanwhile, 48 kilometers north of Siem Reap, has been identified as the location of the medieval city of Mahendraparvata, or the Mountain of Indra -- King of the Gods.
This makes Angkor the world's largest urban conurbation prior to Britain's 18th-century Industrial Revolution -- a revelation that completely alters how experts are looking at the area.
While the ancient urban network's existence was mentioned in inscriptions and long suspected by French archaeologists working in Cambodia, it couldn't be confirmed due to the remoteness of ruins already discovered on the plateau, the inaccessibility of much of the mountain and the existence of landmines installed by the Khmer Rouge.
One of the authors of the NAS report, Australian archaeologist Dr. Damian Evans, is director of the University of Sydney's Robert Christie Research Centre in Siem Reap and the chief architect behind the costly LiDAR mission.
He brought together eight different archaeological organizations, including the Cambodian government's APSARA Authority, which manages the region's archaeological sites, to form the Khmer Archeology LiDAR Consortium, which raised funds for the project and shared data.
The LiDAR mission was conceived to fill in the blank spaces on the map of Angkor, Evans says, as we slip into the jungle just outside the walls of Angkor Wat.
"Nothing on the forest floor is random, not even a termite mound," Evans explains as he points out anthills.
"While a lot of the city is buried beneath the ground, it impacts the surface in subtle ways. The movements, activities and actions of these people hundreds of years ago remain inscribed into the landscape.
"None of these lumps and bumps and dips made any kind of sense, but once you see the LiDAR imagery, it's strikingly evident that what you're looking at are the remains of a city associated with Angkor Wat."
Using technology to speed things up
Out of the sight of the one million tourists who visit the temple-city every year, archaeologists are at work on excavation projects.
They use found remnants of the region's rich Khmer history, culture and way of life to piece together a story that's continually developing, changing visitors' understanding and experience of Angkor in the process.
Archaeologists have worked on the ground here since naturalist Henri Mouhot stumbled upon Angkor Wat in 1860, excavating temple ruins deep within jungles for visitors to tour, peeling away vines from palaces for us to explore and unearthing riches to be displayed in museums.
For many archaeologists, a discovery can represent a lifetime's work. The LiDAR technology changes all that, speeding up the process.