History
Built in the jungle: the ancient cities the forest hid
Calakmul, El Mirador, Ciudad Perdida, Koh Ker, Mahendraparvata, Kuelap: off the circuits, inside the vegetation. The photos are of Khmer sites in Cambodia, used as atmosphere images for the whole theme.
The jungle is the best custodian of ruins there is. It covers them, keeps them humid, leaves them where they are. That is why beneath the planet’s tropical forests lies a quantity of civilisation that school textbooks have barely touched. The forgotten capitals, the cities nobody ever “discovered” because local people always knew where they were, the complexes that technology has made legible only in the last fifteen years. This piece chooses seven, on three continents, and closes with the technology rewriting the map: LiDAR.
Why in the jungle
The great tropical civilisations were long a paradox for archaeologists. Rainforest consumes wood, textiles and paper; the soil is poor; the population densities seemed impossible. Yet the Maya, the Khmer, the Tayrona and the Chachapoyas built enormous cities precisely there, managing water with canals, reservoirs and terraces and farming in ways we are only beginning to understand. When these societies collapsed, through drought, war or political failure, the forest took everything back within decades. The stones remained, under the roots.
1. Calakmul, Mexico: capital of the Snake Kingdom
In the heart of the Calakmul biosphere reserve, in the state of Campeche, two hours of dirt road from the nearest highway. It was the capital of the Kaan dynasty, the Snake Kingdom, and for much of the Classic period the great rival of Tikal, with which it fought a war of centuries. It had perhaps fifty thousand inhabitants, more than six thousand recorded structures, and Structure II, a forty-five-metre pyramid rising above the forest canopy: from up there you see only trees to the horizon and, far off, the outline of another pyramid. Howler monkeys, toucans, jaguars nobody sees but everybody hears. It is the largest and least visited of the open Maya sites.
2. El Mirador, Guatemala: the greatest pyramid
North of Tikal, reached by two days’ walk through the Petén forest or by helicopter. El Mirador flourished in the Preclassic, between 300 BC and AD 150, centuries before the famous Maya cities, and holds the Danta complex: a platform with a pyramid reaching seventy-two metres, by volume among the largest constructions of the ancient world. The raised causeways of white lime, the sacbeob, linked El Mirador to other centres for tens of kilometres. The collapse, around AD 150, was probably environmental: too much lime made by burning too many trees. The forest returned, and the city reveals itself only to those already inside it.
3. Caracol, Belize: the city that defeated Tikal
In the Maya hills of western Belize, in the Chiquibul forest reserve. Caracol was a city of perhaps a hundred thousand that in AD 562 defeated Tikal in battle and interrupted its dynasty for over a century. Caana, the “sky palace”, at forty-three metres is still the tallest construction in Belize, modern or ancient. But Caracol matters above all for another reason: in 2009 Arlen and Diane Chase flew it with the first large-scale archaeological LiDAR and discovered in four days more terraces, roads and structures than they had mapped in twenty-five years on foot. The revolution began here.
4. Ciudad Perdida, Colombia: the city of stairs
Teyuna to the Kogi and the Arhuaco, who are its custodians; Ciudad Perdida to everyone else. On the Sierra Nevada de Santa Marta, at thirteen hundred metres, built by the Tayrona around AD 800, six hundred and fifty years before Machu Picchu. You arrive only on foot, four or five days of trekking through mud, rivers and heat, and at the end a stairway of twelve hundred stone steps climbs through the mist to a series of circular terraces where the houses stood. It was “found” in 1972 by tomb robbers; the indigenous communities had always known it was there. Today the site is managed together with the Sierra communities, and their ceremonies close the city several weeks a year.
5. Kuelap, Peru: the fortress in the clouds
In the Amazonas region, on the eastern slope of the Andes, where the mountain descends toward the Amazon basin and the forest is one of perennial cloud. The Chachapoyas, the “cloud people”, built at three thousand metres a walled platform six hundred metres long and up to twenty high, with more than four hundred circular buildings inside, decorated with zigzag friezes. It predates the Incas by several centuries; they conquered it with difficulty. Bromeliads grow on the walls, the mist rises from the valley floor, and the view from the funnel entrance, a slot in the wall little wider than a person, is one of the strongest architectural experiences in the Americas. Since 2017 a cable car has made access easier.
6. Koh Ker, Cambodia: the Khmer pyramid
Eighty kilometres north-east of Angkor, for twenty years, between 928 and 944, it was the capital of the Khmer empire under Jayavarman IV. In that short time it built dozens of temples and the Prasat Thom, a stepped pyramid of seven levels and thirty-six metres, unique in all Khmer architecture, that seems to come from the other side of the world. Around it, the bases of colossal statues (the figures are in museums, and some have recently returned) and a dry forest that in summer takes the colour of gold. In 2023 it entered the UNESCO World Heritage list; it is still nearly empty.
7. Mahendraparvata, Cambodia: the city on the mountain
On Phnom Kulen, the sacred mountain north of Angkor where in 802 Jayavarman II proclaimed himself universal monarch and founded the empire. For centuries it was known that up there were temples scattered in the forest and a river with a thousand linga carved into its bed; nobody imagined a city. In 2012 and again in 2015 the LiDAR campaigns led by Damian Evans revealed an urban grid of tens of square kilometres: roads, dams, reservoirs, a palace, terraces. Mahendraparvata was a planned capital, with a hydraulic infrastructure anticipating Angkor’s by two centuries. You visit on foot, among trunks and small brick sanctuaries, and almost everything is still under the vegetation.
LiDAR: seeing through the leaves
Light Detection and Ranging is a laser mounted on a plane or drone that fires hundreds of thousands of pulses per second at the ground. Some bounce off leaves; a small percentage passes between one leaf and another and touches the earth. Software keeps only the last returns and reconstructs the bare surface, without forest, to centimetre precision. The result is a map in which roads, terraces, canals and platforms appear as reliefs in a naked landscape. In fifteen years it has changed everything.
- 2009, Caracol. The first large-scale flight; two decades of ground survey surpassed in four days.
- 2012 and 2015, Cambodia. Mahendraparvata and the cities around Angkor: the Khmer empire was larger and more urban than any estimate.
- 2018, Petén, Guatemala. The PACUNAM project maps 2,100 square kilometres and counts more than 60,000 structures: lowland Maya civilisation had a population estimated in the millions, with intensive agriculture, fortifications and raised highways.
- 2022, Bolivia. In the Llanos de Mojos, in the Amazonian savannah, the great settlements of the Casarabe culture appear, with earthen pyramids and canals: tropical urbanism went far beyond Mesoamerica.
- 2024, Upano valley, Ecuador. Stéphen Rostain and his group publish in Science a network of 2,500-year-old garden cities at the foot of the Amazonian Andes, with roads straight for kilometres and thousands of platforms. The “virgin” Amazon was, in part, a built landscape.
What all this tells us
That the concept of “discovery” should be used with care: nearly every site on this list was known to local communities, who kept its names and stories. That tropical civilisations were one of the normal forms of human urbanism, hidden from our sight only by the pace at which the forest grows. And that the map of the ancient world, in 2026, is still open: every LiDAR campaign adds cities, and the forest still has much to give back.
Photo credits: all images under the Unsplash License. Authors: allPhoto Bangkok (cover), James Wheeler, Laurentiu Morariu, George Bakos, Siborey Sean, Florian Hahn, Vicky T, Melody Temple, Dick Hoskins, Sebastian Latorre.
