Chris Leadbeater explores Colombia's mysterious interior and encounters the remnants of a forgotten civilisation.
The beast in front of me is not friendly. There is a dark glint of aggression in its eyes, and the teeth that protrude from its upper jawline have a sharpness that could almost be described as vampiric.
Actually, let us dispense with "almost". This angry visage may have been cut into stone as long as 2000 years ago, but it still bristles with silent menace.
I suppose this might be appropriate. Colombia is, after all, a country where - we have been told - one should look to the shadows for signs of danger.
Play a game of word association with South America's most north-westerly country as the central topic, and the results are unlikely to be positive.
"Drugs" will be there. So will "guerilla".
"Cartel", "kidnap" and "unrest"? Those too.
Colombia is a place that has long been damned by its headlines.
None of these terms occur to me as I wander the Parque Arqueologico de San Agustin on a sunlit morning. Aside from my companion, the only flickers of threat are the loud calls of two warring male mountain toucans deep in the trees that frame the picture.
Around me, an expanse of grass is filled with rounded slabs of grey volcanic rock, each one carved with faces and outlines that, while apparently human, bear animalistic bents - the features of snakes, birds and, in the case of the focus of my attention, snarling jaguars.
They are tomb guardians, designed to protect the dead of a civilisation that vanished long before the Spanish stamped through these hills. And they are wonderful - figures imbued with as much mystique as the moai of Easter Island.
Listed as Unesco World Heritage jewels since 1995, they are the sort of shards of the past that you cross continents to view. And Colombia has been coming closer, in terms of what is realistically accessible, for a while now.
Although the civil war which has festered for 50 years - an internecine struggle between the government and rebel groups which erupted in 1964 along the Cold War faultline, but which has since morphed into a bloody battle over the region's notorious cocaine trade - is still technically in motion, the bursts of gunfire have receded to the blurry margins.
The Foreign Office still warns against forays to certain rural areas and border zones, but also states that "most visits to Colombia are trouble-free".
Intrepid travellers have already noted the beauty of Cartagena and the Caribbean coast - but now the interior, for so long a cause for worry, can also be explored.
This is my intention when, at the start of my Colombian journey, I arrive at the domestic terminal of Bogota's El Dorado airport to find a scene bereft of any noticeable tension or security paranoia.
In the queue for check-in, two nuns in long robes wait their turn behind a gaggle of teenagers pawing at smartphones. My passport earns barely a glance before I amble through to a concourse that feels more bus terminal than aviation hub, planes idling like red double-deckers.
Indeed, the main risk of flying within Colombia might be the peril of accidentally stepping onto the wrong aircraft amid such informality.
Weaving through a sea of bodies, I find my seat on the flight to Neiva. The capital of the mountainous department of Huila lies some 300km south-west of Bogota - a quick one-hour flight, but also a grand leap that will carry me far from the big metropolis.
The guide I meet on landing is in love. With his surroundings. The voice that glides from the mouth of Francois Van Malderen strolls the avenues of his Parisian birthplace, but his heart has belonged to Colombia for 20 years - since he paused during a trek from Mexico to Chile and realised that he was happy where he was. He married and opened a small hotel, La Casa de Francois, in San Agustin.
"I saw no real reason to leave," he answers with a shrug.
It is not difficult to grasp what he finds so alluring about Huila. The Rio Magdalena, the longest river in Colombia, pours through the middle of Neiva, its soupy currents singing of hidden depths; of waters dispatched from Andean slopes on a 1500km mission to the Caribbean Sea.
We halt at restaurant Gran Vinos, chewing at medallions of peppered beef as soft lunchtime chatter floats around us. Outside, a striking composition by Colombian sculptor Rodrigo Arenas Betancourt hints that the locals were not always so welcoming.
Its bronze menagerie of tumbling horses and falling conquistadors salutes the 1539 rebellion of the indigenous Yalcon people which briefly slowed Spanish incursion.
The drive to San Agustin - a meandering south-westerly adventure of 240km, largely along Ruta 45, tracing the Magdalena back towards its source - throws out hints of its own.
South of Neiva, a military checkpoint tacitly acknowledges the ongoing insurgency, but in a visibly unenthused manner, one soldier eyeing passing traffic with minimal interest; his colleague dozing in a chair, his automatic rifle laid against the fence behind him.
Beyond, a pale wall in the town of Campoalegre bears eloquent testament to frustration at a half-century of division, the words "Mejor vivir para algo que morir para nada" (It is better to live for something than to die for nothing) scrawled high in graffiti.
There are fragments of beauty too.
Outside Campoalegre, a viewpoint rears suddenly above the Magdalena, displaying a curve of the river - as, alongside, three young men play dominoes next to a shack that sells coffee and cakes, their pieces clacking on the table.
In Gigante, a huge ceiba tree dominates the main square - an arboreal behemoth spreading its arms over the town. And when, after six hours, we roll to Akawanka Lodge (website in Spanish), a homely retreat on a hill above San Agustin, it is in time to see the sun set on the valley.
Dawn brings a day of promise. For, in their own discreet way, the historic treasures of San Agustin are kindred spirits of Machu Picchu or Chichen Itza - illustrious totems of an advanced people whose bright era was extinguished.
The added mystery here is that, where the Incas and the Maya were defeated by Spanish might, when the conquistadors arrived in this lofty landscape, the creators of these intricate sentries of the deceased had already departed.
Archaeological research suggests theirs was an agricultural society that flourished from 200BC to AD1300, yet disappeared without explanation. They slipped into the mist of yesteryear so successfully that they did not leave a name. Only the stones.
Certainly, entering the national park feels like a moment of ingress into a lost world - a plain wooden gateway; a visitor book to be signed - the signatures therein Colombian or Ecuadorian, but rarely European. And then, inside, these splendid relics - an outlandish hybrid of eagle and man, a snake trapped between his clawed fingers; two female statues that flirt with the idea of pregnancy, nine lines dashed across their bellies, hands clutched in front; the big-cat growl of the sculpture that intrigues me most, its feline growl perhaps linked to an Andean myth of a woman who slept with a jaguar and birthed a warrior race.
Together, they speak for a civilisation that no longer has a voice.
And yet they were mute witnesses - not so much grave markers as afterlife aids that were buried with the dead. That their patterns were not meant to be seen, nor their tales told - but were unearthed by tomb robbers or via later excavations - makes the craftmanship all the more remarkable.
Whoever they were, these invisible Andeans were an ingenious people. So much is clear in the Fuente de Lavapatas - a stream bed where channels sliced into the rock shed further meagre light on their story.
When the stream is dry, these hand-gouged channels keep their own counsel. But when the rain comes, they reveal themselves, directing the water through shapes and designs that were previously unapparent - frogs, lizards, the faces of children, a woman in labour. The stream was probably used for religious rituals.
Their influence extended beyond what is now San Agustin. Thirty kilometres north, on the opposite side of the Magdalena, the enclave of Alto de los Idolos continues the theme. Its lustrous sweeps of grass would be redolent of a golf course were it not for the artworks that stand proud.
Here, too, maybe, is a clue. Does the inclusion of snap-jawed crocodiles and needle-mouthed caymans among the bestial flourishes suggest that these forgotten souls knew of, and perhaps decamped to, the Amazonian wetlands to the south and east?
My day will end at the Estrecho del Magdalena, a narrow gorge in the great river, where I dangle my feet above the flow as Francois skims pebbles on the surface. But before this, I spot a board by the entrance to Alto de los Idolos. It declares the number of people who explored the site in 2012 - a total undramatic enough that it can be split into chunks. Of the 19,840 visitors, only 3975 were foreigners - of which 203 hailed from the UK.
It is not just the grave stones of San Agustin, but Colombia itself, which remains a secret.