Researchers have discovered human footprints in Mexico from as far back as 25,000 years ago.
The five markings, found in a remote area in the northern part of the country, appear to belong to adults and possibly a child.
They "are among the few impressions of the first inhabitants in the American continent found Mexico," the Institute of Anthropology and History said, according to the Herald Sun.
The humans likely lived in caves, researchers said.
"It took us a lot of work to find them because they are not easily identified," said anthropologist José Concepción Jiménez.
The findings, which are between 4,500 and 25,000 years old, were discovered by a local resident.
Jiménez said that the resident e-mailed him to tell him of the discovery in the Ahuatos Valley in the municipality of Bocoyna, according to Efe.
"After several searches we found them in a stream running down an incline in a place of approximately 1,000 square meters (1/4 acre). The imprints are located in an area about 2 meters (6 1/2 feet) into the stream that only has water during the rainy season and is dry the rest of the year," he told the wire service.
One of the prints was likely made by the right foot of an adult male; another footprint might have been the left foot of another adult. The footprint of the child, meanwhile, indicates that she or he was about 3 or 4 years old.