Fishermen working on the Solimões River, near the municipality of Tabatinga, in the region of the Brazil-Colombia-Peru triple border, spotted the artifacts.
To their surprise, they were two cannons that originated with the Portuguese crown.
One of the pieces was buried on a beach that appeared with the Solimões River's low tide.
The other had part of the artifact out of the water.
Each cannon can weigh more than two tons.
The archaeological find was only possible due to the severe drought that has hit the Solimões River in Amazonas.
According to the Brazilian Geological Survey, this is the worst drought in 42 years in the municipality of Tabatinga.
The two cannons were found in front of the city's waterfront, about 200 meters from the ruins of the São Francisco Xavier de Tabatinga Fort.
The artillery pieces were installed to help the troops defend the Portuguese Crown's domain against Spanish expeditions in the region.
There are records of travelers from the 18th century who report the presence of the cannons in the Portuguese Fort.
The military building was destroyed in 1932 by the collapse of the ravine on which it was built.
This is a phenomenon known as 'Fallen Lands', very common in the rivers of the Amazon.
In the following years, the Fort was covered by the waters of the Solimões River.

Fonte: Agência Amazônia