Countless tourists visit Brazil’s Sucuri River every year to explore the crystal clear waters running through lush forested areas. But on one recent expedition, tourists managed to spot one of the area’s most legendary inhabitants.

It was hard to miss.

Tourist guide Celio Araújo has been working in the region for more than two decades, taking groups down the river in small boats, but in all that time, he has not often encountered a sighting like the one that occurred earlier this week.

While traveling the river, the group noticed a prominent shadowy figure lurking beneath the water.

As it turned out, it was a massive anaconda on the move.

It was estimated by Araujo to be about 20 feet long!

While anacondas are often impressive in size, they are notoriously skittish and difficult to spot while camouflaged in a thicket. But this anaconda swimming down the river allowed us to see its massive form fully but fleetingly.

” How many of them have I not seen? They are always rare,” Araujo told The Dodo publication. ” At the sight of the swimming animal, tourists were very excited.”

Anaconda hopes that by recounting such encounters, people will develop a new sense of awe and respect for the anaconda, a species often considered menacing but more inclined to coexist peacefully with humans.

” At the sight of humans, their first reaction is to run away,” says Araujo. “They always keep their distance, and so do we.”