A severe drought in Brazil's jungle city of Manaus has caused the level of the Rio Negro river to fall and brought out some eerie artwork sculpted onto the rocks, local media reported.
The engravings were dubbed "Caretas," which roughly translates to "little faces". Some faces are slightly square, and none of them has more than a head, a mouth, and sometimes a nose.
Some of the figures are reportedly still submerged in the rocky clump, but are expected to become visible soon if the Rio Negro continues to recede. During the 2010 drought, the lower gravels were only visible for one day and then came back underwater when the river level rose again.
According to experts, it is impossible to say how the artworks were made and whether it was during a time of severe drought or if the river level more than 1,000 years ago was lower than it is today.
The archaeologists noted that the "emojis" bear a striking similarity in style to other images of heads engraved along several river outcrops in the central Amazon region.
They pointed out that these rock art sites also share a common feature: they are only visible during periods that the river is drying and are often close to ancient pre-colonial indigenous communities.
Archaeologist Jaime Oliveira called the work "complex graphic art" and believes it was made with axes made from hewn stone.