Canaima National Park

Long ago, layers of sand turned into hard rock.

Water and weather wore the rock away, leaving flat-topped mountains.

NASA explains that the tepuis are what is left of a sandstone plateau that once covered granite rock 1.7 billion years old. Layers of sand were pressed and cemented together into sandstone and quartzite thousands of meters thick.

After the land was lifted up about 180 million years ago, erosion broke the plateau apart into separate mountaintops. The tepuis rise 1,000 to 3,000 meters, and NASA calls them some of the oldest geologic formations in South America.

According to NASA, the tepuis are remnants of a once-continuous sandstone plateau that covered a 1.7-billion-year-old granite basement. Layers of sand were compressed and cemented into sandstone and quartzitic rocks thousands of meters thick. Following tectonic uplift about 180 million years ago, erosion broke the plateau into isolated mountaintops, 1,000 to 3,000 m high.

Venezuela's national parks institute, Inparques, dates the tepui rocks to the Precambrian.

Angel Falls drops from the top of a tepui.

The water in the Canaima lagoon looks reddish.

NASA says Auyán Tepui is home to the tallest waterfall on land: Angel Falls drops nearly 1,000 meters, 19 times higher than Niagara Falls. Inparques gives its height as 979 meters.

The Laguna de Canaima in the west of the park is fed by the Carrao River. Inparques says its water has an intense reddish color and its sand beaches are pink, because of tannins from decaying plants and quartz.

UNESCO counts the world's highest waterfall (1,000 m) among the park's cliffs and falls; NASA says Angel Falls on Auyán Tepui drops nearly 1,000 m, 19 times higher than Niagara Falls, and Inparques gives 979 m.

Inparques describes the Laguna de Canaima, in the western sector, as fed by the Carrao River, its water an intense reddish color and its beaches pink because of tannins from decomposing vegetation and quartz. A wall of falls (Hacha, Golondrina, Wadaima and Ucaima) pours into it.

Some tepuis have long caves inside them.

Scientists found a long cave there in 2013.

NASA says that, like many tepuis, Auyán Tepui has extensive cave systems. In 2013 researchers discovered one of the longest quartzite cave systems in the world there: the Imawarì Yeuta caves, with three entrances, three rivers and at least 22 kilometers of tunnels.

Because the caves run through quartz sandstone, water wears them away less easily. They form slowly, perhaps over tens of millions of years.

Auyán Tepui contains extensive cave systems (NASA). In 2013 researchers discovered the Imawarì Yeuta caves, one of the longest quartzite cave systems in the world, with three entrances, three rivers and at least 22 km of tunnels.

Running through quartz sandstone, tepui caves are less susceptible to water erosion and form slowly, perhaps over tens of millions of years. In other tepui caves of the region, researchers have discovered new minerals and new species of bacteria and blind fish.

Jaguars, monkeys and sloths live on the lower slopes.

Some plants on top catch insects for food.

NASA says that because the tepuis stand high above the forest, they are home to some plants and animals found nowhere else on Earth. About one-third of the plants on the mountains are endemic.

Monkeys, jaguars, pumas, sloths and several kinds of bats live on the lower slopes, and snakes, iguanas and lizards live on the summits and slopes. Inparques says carnivorous plants such as Heliamphora and Drosera grow on the summits and catch insects for nutrients.

Standing high above the forest, the tepuis are home to some animal and plant species found nowhere else on Earth; about one-third of the vegetation on the mountains is endemic (NASA). Mammals on the lower slopes include monkeys, jaguars, pumas, sloths and several bat species; reptiles such as snakes, iguanas and lizards live on the summits and slopes.

Inparques notes that in the nitrogen-poor rocky soils of the summits, endemic carnivorous plants such as Heliamphora (marsh pitchers) and Drosera get nutrients by trapping and digesting insects.

Wear long sleeves and use bug spray to stop mosquito bites.

A hat and shade help protect your skin from the sun.

Inparques says tourism led by guides from Pemón communities helps visitors respect the fragile savanna.

The US Centers for Disease Control and Prevention (CDC) says mosquitoes bite day and night. Use an EPA-registered insect repellent and wear loose, long-sleeved shirts and pants. To protect your skin from the sun, stay in the shade, use sunscreen and wear a hat with a brim all the way around.

Inparques notes that sustainable tourism driven by guides from Pemón communities ensures that visitors respect the fragility of the savanna.

The CDC advises using EPA-registered insect repellents and loose-fitting, long-sleeved shirts and pants, since mosquitoes bite day and night and their bites can make you sick. For sun safety it recommends shade, sunscreen, protective clothing and a hat with a brim all the way around that shades the face, ears and back of the neck.