In an age of satellite technology and cheap air travel, few corners of the planet remain undiscovered. But southern Venezuela’s tepuis – the sandstone, table-topped mountains that inspired Sir Arthur Conan-Doyle’s novel The Lost World – still make travellers feel like 19th-century explorers setting off into the hinterland.

Towering over the surrounding forest, the tepuis have almost sheer vertical flanks; and while you are unlikely to see the dinosaurs and prehistoric animals that Conan-Doyle imagined, the area is full of strange geological formations and carnivorous plants.

The most accessible tepui, 2,180m-high Roraima, was unexplored until 1884. Today, the plateaued summit is home to small waterfalls, natural quartz-lined pools and Punto Triple, the point at which the borders of Venezuela, Brazil and Guyana meet.

At first glance, the 30sqkm sandstone surface seems barren – a contrast to the rainforest teeming with life below. But many extraordinary plants have adapted to the environment, including carnivorous sundews, bladderworts and march pitchers, all of which trap mosquitoes and other insects. Rain has carved out small canyons and caves where travellers can pitch their tents, and erosion has created bizarre rock formations, including one that is said to resemble former Cuban leader Fidel Castro.

Tour companies such as Backpacker Tours and Kamadac organise six-day guided hikes to the summit from the nearby town of Santa Elena de Uairen. While the tour groups often provide equipment like tents and sleeping bags and stop at established campsites along the way, the hikes can be demanding, especially during the rainy season between June and October, so visitors should have a decent level of fitness before ascending. Those with deep pockets but little time or energy to hike can charter a helicopter from Raul Helicopters.

A less demanding tepui experience can be found further north at Auyantepui, a plateau where US pilot Jimmy Angel crash-landed his plane in 1937 when looking for gold in the region. When he and his three passengers began the trek back to civilisation, they stumbled across the world’s highest waterfall, known to the local Pemon people as Kerepakupai Vena. Today, the 979m-tall falls bear Angel’s name.

Trips to Angel Falls start in the village of Canaima, which sits on the edge of a palm-fringed lake facing a series of beautiful cascades in Canaima National Park. Canaima is only accessible by air and visitors can fly in directly with Conviasa airline from Simón Bolívar International Airport near the capital, Caracas.

Tour companies like Bernal Tours and Excursiones Kavac, which run two-day trips to the falls from Canaima, can also arrange charter flights from Ciudad Bolivar, the capital of Venezuela's southeastern Bolivar state, or Puerto Ordaz, a city in the east of the country.

After an afternoon spent visiting Canaima’s 40m-tall Sapo Falls, where visitors can walk behind the thundering water as it plummets over the side of the cliff above, tours head to the base of Angel Falls in small boats, winding their way up the Rio Carrao and stopping for a picnic lunch at the Pozo de la Felicidad (the Pool of Happiness). The three-hour boat trip often seems shorter as visitors take in the stunning scenery of the tepuis rising majestically on both sides of the river -- but those who make the trip in dry season (roughly between December and April) may have to get out and push the boat through particularly shallow patches.

By the time you reach the island of Isla Ratoncito, the falls are already clearly visible, but a one-hour hike through the rainforest to the viewpoint of Mirador Laime brings them even closer. From the viewpoint -- a simple collection of rocks approximately 100m from the base of the falls -- the cascade is tall and thin, like a white ribbon tumbling down the sheer rock face. Even here, travellers have to strain their necks to see the top. Despite Angel Falls’ fame, only small groups of visitors make it this close to the roaring water – a remote spot that still offers up an exclusive experience.