A group of adventurous tourists thought they were approaching a flock of sheep on a hillside. When they got closer, however, they realized just how wrong they were. What they found instead is something we thought impossible.

Wrangel Island Nature Reserve in the Arctic provided adventurous tourists with an expedition they will never forget after they happened upon something never seen before. As the group approached the island aboard the vessel Akademik Shokalskiy, they witnessed what appeared to be a flock of grazing sheep. Soon, however, they would realize how wrong that assumption was.

“What we saw (and experienced) next will rewrite expedition travel experiences,” Rodney Russ, the expedition leader, recalled, according to iExpedition. Russ knew it would be impossible for there to be sheep on the remote Arctic island in the Chukchi Sea above Siberia, Russia.

“We launched the zodiacs for a closer look, and that is the memory we will all carry with us,” Russ added. “There are no words to describe it.” As the team took out their binoculars, they realized they weren’t looking at a flock of sheep but rather a gathering of polar bears — and not just a few. With more than 200 polar bears congregating on a hillside, it was an unusual sight to be sure.

Polar bears are usually solitary animals, but these Arctic predators had gathered by the hundreds. Although it’s not unusual to see the typically solitary creatures occasionally gathered together, this sheer volume of bears was a first. Having completed numerous voyages to Wrangel Island, Capt. Rodney Russ said he had never seen more than a dozen polar bears in one location before. It’s “one of those days I or anybody else with me will never forget,” the expedition leader added.

Blaming climate change, some believe sightings like this could become more commonplace. “Wrangel Island hosts the highest density of polar bear dens on the Earth, with as many as 400 mother bears utilizing the island each winter to raise their young,” Mother Nature Network explains.

“Over the last several years, the population density on the island in the summer has increased to historic numbers due to the disappearing ice packs that once enveloped the island, forcing the bears to remain land-locked,” the outlet claims. “Though thrilling to witness, such large polar bear gatherings are not normal, and they could represent signs of ecological stress.”

But, the mystery behind what caused the abnormal site was quickly solved. So, what brought the large, unprecedented gathering bears together? The same thing that often brings people together: Food. The gathering of more than 200 strong was lured by the scent of a whale carcass that had drifted into the shallows, according to Adventure Sports Network. Nature had rung the dinner bell.

The bears concentrated around the massive whale carcass after it washed ashore, providing an easy meal. Powerful carnivores typically become aggressive toward one another while feeding or during the hunt, but apparently, a whale carcass provides plenty of food to go around, so the unusual get-together was a peaceful one, making it an even more remarkable site.