Caves, San Pedro de Atacama

Until a few years, this amazing cave was almost unknown for most visitors to San Pedro, but recently it was included in the schedule of tours visiting the Moon Valley.
I used to visit it at least once on every trip to San Pedro, and slept inside it every time I could, as it is a nice place to spend the night.
The cave was formed by a prehistoric underground river –some scientists date it at around 4 million years ago- which carved the bizarre (to say the least..) inner shapes, which resemble those of an ear, and also the pits and chambers deep inside of the cave: there are places so low that one only can go through them crawling on the belly, and others where inner “cathedrals” and domes rise 10 metres up from sandy floors.
Tours –even the dedicated ones- go only for the first metres, and no more than 300 metres from the entrance, although it is possible to explore it for at least 4 kilometres, with relative ease, in 1 or 2 days.
The cave has some “hatches” leading to the top of it, which are useful if you want to take a breath of fresh(er) air...or if somebody feels claustrophobia.
In the night, stand in complete silence in it, and listen for the salt making crackling sounds as it expands and contracts according to the changes in the temperature, but as well due to the humidity and heat of your body, which makes it crack too.
A headlamp is ESSENTIAL, as well as spare batteries and water, because all what surrounds you is salt, extracting the water from your body like a sponge. Clothing that covers your skin is necessary too, as the salt floor and walls makes bruises and wounds that take long time to heal, and so do the sharp salt needles protruding everywhere.
After the first kilometre, there are deep pits, so be careful if exploring beyond that point.
It can get chilly in the night, as a cold desert breeze runs along the tunnel; this breeze gets in through the hatches.