Image copyright Alex Guillen Image caption Alex Guillen and Natalio Gonzalez document the highlands’ peak temperatures in Bolivia
In the highlands of Bolivia, temperatures are consistently between 37C and 43C (99.6F and 102F) all summer.
Natalio Gonzalez, a photojournalist with the government agency Telespazio, says the region’s sun is “scary” and has a power to make people “light-headed”.
“It’s a really volatile place. It can literally put you in a coma,” says the 33-year-old.
He describes some of the areas where he photographed as tropical heat.
“The colour of the clothes they wear can change in the seconds they take off in this place,” he says.
Some people have gone as far as not leaving the house at night when the sun has set because they cannot wear a hat or clothing.
Image copyright Alex Guillen Image caption Residents flock to the glimmering waterfalls at Fruejwasilla
Mr Gonzalez says solar radiation is not helping their battle to keep cool.
The clouds in the horizon that keep the sun down are almost non-existent, leaving the peaks exposed to “black sand” – a medium that can stay in the sky far longer than the light of day.
“This sun isn’t normal,” Mr Gonzalez says.
“It isn’t even like in the sea, where the water is softer. This here is black sand, the colour of gold.”
The highlands of southern Bolivia have an unusual geological history that even has a name: the Moqueta Centre, after the Moqueta volcano.
It dates back to before an explosion in 1952, which made the earth swell and the form a waist of molten rocks called caudalos.
They are the source of the solar radiation the Andean people get through the year.
Image copyright Alex Guillen Image caption Animal keepers and hikers show off the usual wildlife including foxes
Mr Gonzalez says the contrasts are hard to ignore:
“It’s the most beautiful place on earth. The hills are spectacular and it’s the country I lived in for the last 16 years. But then it’s like walking on a beach with no drink, no sunblock, no breeze. It’s borderline schizophrenic.”