There is a universe of silence in this lost world. It has been absolute. Your footsteps are the first sound, perhaps for millions of years.
As Francesco Sauro and his team abseil into caves beneath the table-top mountains (<i>tepuis</i>) of Venezuela and Brazil, they are venturing into the unknown, meeting daunting challenges as they descend into some of the remotest
and possibly oldest caves on the planet.<br><br>The caves’ quartzite rock is far harder than in the limestone caves found around the world. In nine expeditions to the <i>tepuis</i>, Sauro has established that
some of their unique life forms, such as the bacterial colonies that inhabit the deepest caves, mobilize silica from the surrounding rock, making them different from much of life on Earth, which uses and consumes carbon or sulphur.
Sauro says analysis of these bacteria gives a window into the evolution of life on the planet.<br><br>At the same time, Sauro is employed as a leading instructor of astronauts by the European Space Agency, and uses caves
as a laboratory to prepare humans for life on other planets. “We have come to realize that, in the next expeditions to the Moon or Mars, people will have to live off the planet for many months – and that caves provide a perfect, safe
environment for that,” he explains. As one of the world’s foremost speleo-geologists, Sauro is using his geological knowledge to help pinpoint promising regions on the Moon and Mars where Earth-like formations may have caused suitable
caves to form.