Sima Humboldt

La cueva sima Humboldt - Sima Major

Useful Information

Location: Parroquia Aripao, Municipio Sucre, Bolivar State, Venezuela.
Sarisariñama Tepui, El Caura Forest Reserve, Jaua-Sarisariñama National Park
(4.685503, -64.218624)
Open: no restrictions.
Fee: free.
Classification: KarstTiankeng SpeleologyQuartzite Karst Caves
Light: n/a
Dimension: L=352 m, W=245 m, VR=314 m.
Guided tours: self guided
Photography: allowed
Accessibility: no
Address: Sima Humboldt, Parroquia Aripao, Municipio Sucre, Bolivar State, Venezuela.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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25-NOV-1961 discovered by famous jungle pilot Harry Gibson.
1974 descended for the first time by an expedition led by Charles Brewer-Carías and David Nott.
1976 explored by a Venezuelan-Polish expedition.


Sima Humboldt (Humboldt Abyss) is one of two tiankengs on Sarisariñama Tepui, as it is the bigger one it is also named Sima Major (Big Abyss). It is located in the El Caura Forest Reserve and the Jaua-Sarisariñama National Park. There are numerous similar structures on the only forested tepui, all of them having a patch of forest on the bottom. However, there are two which are more or less circular sinkholes. A third one, which is also of decent size is quite elongated, more like a gorge, the other structures are located at the rim and thus open to one side. However, all of them were formed by the same karst processes and from a certain point of view are the same structure. The tiankeng has overhanging walls, the maximum width at the surface is 352 m, while it is 502 m wide at the bottom 314 m below.

The tiankengs were discovered by famous jungle pilot Harry Gibson from his plane. But it took until 1974 when the first expedition to these sinkholes was organized by the explorers and adventurers David Nott and Charles Brewer-Carias. Numerous scientists participated in this expedition, which realized a lifetime opportunity to be the first in an unexplored area. They used a helicopter to reach the plateau, and three men descended on seven 50 m long ropes tied together. The important point is that this was actually before the invention of the single rope technique (SRT). Abseiling worked well, but the normal way out at that time was climbing up the wall, supported by the rope. But they realized that the sinkhole became wider to the bottom, the walls were not vertical, they were overhanging. The explorers were trapped. Their colleagues were able to organize a winch a few days later. They lowered a chainsaw and the three men cut giant trees to make an open space for the helicopter. But at last it did not work, and finally they organized rope ladders, which allowed the men to leave the shaft. By the way, a participant of this expedition named Eugenio de Bellard Pietri named the sinkholes after two famous explorers.

The next investigation of both sinkholes was done two years later, in 1976. A Venezuelan–Polish expedition explored both tiankengs and a third one named Sima de la Lluvia. The cave at the bottom was 1,35o m longa and was the longest known quartzite cave for the next two decades.

The Sarisariñama Tepui has its plateau around 2,300 m asl and a surface of 482 km². It was named after a legend of the indigenous Ye’kuana of an evil spirit, which lived in the tiankengs and cried "Sari, Sari" every time he fed on humans. The upper layer is quartzite of the Palaeoproterozoic Roraima Formation. Unlike most other tepuis the plateau is a forest with 25 m high trees, and an enormous biodiversity. The most famous endemic animal on the plateau is the frog Stefania riae.

The next road is 100 km away, so the only way to visit the tepui and the tiankengs is by helicopter or plane. We guess the best way to see it is to hire a small plane for two hours at Canaima airport, which is 230 km to the northeast and a tourist center of sorts. This is definitely not cheap, but it's the tour of a lifetime! In theory, it's possible to actually enter the tiankeng, either with a helicopter or by foot if you are a very good climber. However, it is located in a nature reserve and a national park, and such visits require a permit.