Scientists have discovered the oldest human footprints ever outside Africa, left in a river approximately 800,000 years ago, according to BBC News.

Norfolk scientists from the British Museum, the Natural History Museum and the University of London found the prints left by a small group approximately five people migrating south across the estuary in Happisburgh.

Researchers believe the group consisted of adults and children, including one with the foot size equivalent of a modern size 8 shoe.

"This is an extraordinarily rare discovery," Nick Ashton, of the British Museum, said according to The Guardian. "The Happisburgh site continues to rewrite our understanding of the early human occupation of Britain and indeed of Europe."

The discovery was revealed this week and published in the journal PLOS ONE.

The prints are the first direct evidence of the earliest known humans to exist in northern Europe.

Sea tides that exposed the footprints last May also destroyed them, but not before scientists were able to record them, according to BBC News.

"At first we weren't sure what we were seeing," Ashton said, "but as we removed any remaining beach sand and sponged off the seawater, it was clear that the hollows resembled prints, perhaps human footprints, and that we needed to record the surface as quickly as possible before the sea eroded it away."

By using photogrammetry, scientists were able to confirm what they found was in fact footprints, according to BBC News. Some of the prints were clear enough to reveal heel, toes, and arch.

The scientists are hoping to find more footprints in the area as well. No fossils remains have be found near the area yet however. 

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