Sima Humboldt

Sima Humboldt (Sima Mayor), one of the Most Mesmerizing Caves in Venezuela, is a massive sinkhole on the crest of the Sarisariama Tepui plateau in Bolvar State, Venezuela. It's exceptional for a variety of reasons, including its great size and depth, its location on the summit of the lone forested tepui, the presence of a patch of woodland at its foot, and the weathering process that created it. Alexander von Humboldt, a scientist and explorer, was honored with the feature's name.

It was discovered in 1961 by pilot Harry Gibson, along with the nearby Sima Martel. In 1974, the sinkhole was descended for the first time, and in 1976, it was further explored. It has a volume of 18,000,000 m3 (640,000,000 cu ft), a maximum width of 352 m (1,155 ft) at the top and 502 m (1,647 ft) below, and a depth of 314 m. (1,030 ft).

Another massive sinkhole, Sima Martel, lies only 700 meters from the rim of Sima Humboldt. On Sarisariama, there are four caves in all.

Location: Venezuela, Bolívar (state), Sarisariñama