The city was built 2,500 years ago but may have been abandoned after a volcanic eruption.
A huge ancient city has been found in the Amazon, hidden for thousands of years by lush vegetation.
The discovery changes what we know about the history of people living in the Amazon.
The houses and plazas in the Upano area in eastern Ecuador were connected by an astounding network of roads and canals.
The area lies in the shadow of a volcano that created rich local soils but also may have led to the destruction of the society.
While we knew about cities in the highlands of South America, like Machu Picchu in Peru, it was believed that people only lived nomadically or in tiny settlements in the Amazon.
"This is older than any other site we know in the Amazon. We have a Eurocentric view of civilisation, but this shows we have to change our idea about what is culture and civilisation," says Prof Stephen Rostain, director of investigation at the National Centre for Scientific Research in France, who led the research.
The Europeans always spread the myth that they conquered the Americas because they were somehow superior. The fact is that it was simply because 90% of the population died.
Come on! There is a reason why the fights against the Aztecs and Incas is called a conquest and none in the rest of the Americas is called like that and it is precisely because there wasn't enough of a civilization to make an organized war instead of being just massacred, enslaved or subdued.
It is very normal to assume that if you don't find anything suggesting a large civilization, there isn't any. We are just discovering that we didn't find anything because it was covered over by nature. Nothing different than what happened with North American cities that have also been found in a similar way or with a lot of the Mesoamerican pyramids or even in Egypt 200 years ago.
If you have no understanding of germ theory or how you could indirectly lead to the death of 90% of the population before you even set foot in a place and by the time you do, nature has swallowed everything and the few remaining survivors don't have written records of the history, it's not going to be the normal assumption that there used to be a large civilization in there, especially since some other places did have a more tribal civilization, so it wasn't something strange.
This time it is more about lack of knowledge than European hubris, in my opinion.
There are plenty of historical records about the population dying from diseases. This was in no way unknown. Also, the conquerors actively tried to s destroy all records of the previous civilizations. They knew exactly what they were doing.