Park rangers are fighting a losing battle against visitors willing to risk their lives on the thin ice of a lake in Poland's southern mountains.
Morskie Oko lake is a popular tourist destination all year round, but the sight of people venturing out onto the deceptively thin ice cover prompted the Tatra National Park Rangers to post this urgent warning on at the start of the month: "Tourists, don't go out onto the Morskie Oko ice. It's thin, and can lead to great danger. We appeal to you to use your judgment and act responsibly!"
An accompanying video of people strolling on the ice, oblivious to danger, has garnered more than 112,000 views and made it to the national media, but persistent risk-takers seem undeterred.
In the course of just four hours at the weekend, the Rangers and mountain rescue volunteers issued more than 500 warnings to crowds of people dicing with death on the shores of the lake, reports.
"Tourists have put their lives at risk just to take a selfie. There were even people with small children walking out onto the ice," Chief Ranger Edward Wlazło told "The ice is just over 6 cm (2.3 inches) thick, which is very little."
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Many of the visitors have come from abroad, including Hungary, China, Indonesia, the Philippines, and Ukraine, and told the Rangers they simply didn't understand Polish. But there were Poles among them, too.
One tourist from Hungary got 350 metres (383 yards) out into the middle of the lake before the Rangers were able to turn him back. "The chances of saving him if he'd fallen through the ice would have been small," a spokesman told RMF radio.
When the adventurers return safely to shore, they still face the smaller risk of being fined up to 500 zlotys ($132: £105).
The reaction in the Polish media has been largely one of incredulity. "" is what the Super Express tabloid called it, and social media comment has been even harsher on the "winter bathers".