Only five natural asphalt lakes exist in the world: Pitch Lake in Trinidad and Tobago, La Brea Tar Pits and McKittrick Tar Pits in California, Carpinteria Tar Pits also in California, and Lake Guanoco. What sets Guanoco apart, beyond its size, is its camouflage. While the others expose their dark surfaces to the sky, Guanoco is overgrown -- vegetation covers the tarry expanse, concealing the depth that varies between 1.5 meters and deeper pockets. The lake's asphalt is purer than Trinidad's Pitch Lake, despite Guanoco being larger in surface area but smaller in total volume. The Instituto Venezolano del Asfalto estimated the reserves at 75 million barrels, a figure that has drawn prospectors, corporations, and governments to this remote stretch of Sucre state for over a century.

All natural asphalt lakes were likely formed during the Pleistocene epoch, and they share a common geological mechanism. They are the largest examples of natural oil seeps, created when petroleum migrating upward through rock -- driven by buoyancy, since oil is lighter than groundwater -- reaches the surface instead of being trapped in deeper layers. Near the surface, where temperatures are cool enough for bacteria to thrive and fresh meteoric water surrounds the oil, microbes metabolize the petroleum. This process of biodegradation transforms liquid oil into thick, tarry asphalt. The result at Guanoco is a lake-shaped deposit that has been seeping and thickening for tens of thousands of years, sitting roughly 140 kilometers southeast of Cumana along the Guanoco River.

Long before European prospectors arrived, the Warao people knew what lay beneath the vegetation. They harvested the asphalt to caulk their canoes, waterproofing the hulls for journeys through the rivers and coastal waters of eastern Venezuela. When industrial interests discovered the deposit in the late 1800s, the approach was less practical and more extractive. Beginning in 1897, companies exploiting contractual grey areas set up operations at the lake. A political struggle followed. President Cipriano Castro, who took power in 1900, broke Hamilton's exclusive rights to the deposit -- a confrontation significant enough that Harvard's library holds an 1904 pamphlet titled "The Violent and Illegal Seizure of Bermudez Lake by the Venezuelan Government." Commercial mining of the asphalt continued until 1934, when operations ceased.

By 1998, the area around Lake Guanoco was described as abandoned and underdeveloped, still waiting for asphalt production to restart. The infrastructure that once served the mining operations had decayed. The vegetation had reclaimed whatever ground the machines had cleared. It is a strange fate for a deposit of such value -- 75 million barrels of crude sitting in plain sight, or rather hidden in plain sight, beneath a green canopy in a remote corner of a country with the world's largest proven oil reserves. The Warao's canoes are gone. The corporate prospectors are gone. The lake endures, seeping quietly as it has since the Pleistocene, indifferent to the fortunes and failures of everyone who has tried to profit from what it holds.