Amazing photos show an uncontacted indigenous community living in the depths of the Amazonian rainforest.
The images were taken this week from a helicopter by Brazilian photographer Ricardo Stuckert, and show a way of life almost extinct around the world.
"I felt like I was a painter in the last century," Mr Stuckert told National Geographic.
"To think that in the 21st century, there are still people who have no contact with civilisation, living like their ancestors did 20,000 years ago - it's a powerful emotion."
Mr Stuckert is involved in a project to photograph indigenous tribes across Brazil.
He was on a helicopter journey to travel to a remote outpost when the chopper was forced to change its fightpath due to a thunderstorm.
Suddenly he found himself flying over the primitive settlement of an isolated tribe.
The inhabitants were equally as surprised - greeting the helicopter with a volley of arrows.
"They're messages," indigenous tribe expert José Carlos Meirelles told National Geographic. "Those arrows mean 'Leave us in peace. Do not disturb.'"
The remote tribe is believed to have several hundred members - and they are right to be cautious. Although they are supposed to be protected, many other tribes have been wiped out by illegal loggers, miners, and drug traffickers.
"Once their territory is encroached by loggers or prospectors, the isolated groups are finished," Mr Meirelles said. "They could disappear from the face of the Earth, and we wouldn't even know it."
But for now the tribe is safe, and the meeting was one neither side will forget.
"It was surprisingly powerful and emotional," Mr Stuckert says.
"The experience touched me deeply as a unique event. We live in an age when men have been to the moon. Yet here in Brazil there are people who continue to live as humankind has for tens of thousands of years."