Tourists shocked after innocent vacation activity lands them in hot water with locals

An American couple's morning run through Venice, Italy, took an unexpected turn — and went viral — when they discovered that jogging shirtless could result in a fine.

In a video posted to Instagram last month, the woman documented the aftermath of a morning run through Venice with her boyfriend, who was not wearing a shirt.

She said the two decided to go for a jog through the city's iconic streets when they noticed locals reacting negatively to them.

TOURIST'S CHURCH CLOTHING HACK LEAVES TRAVELERS SHARPLY DIVIDED OVER SACRED-SITE ETIQUETTE "We didn't know that it's illegal to run shirtless through Venice," the woman said.

"We noticed people were like, shaking their heads at us, looking disgusted and angry." She added, "Someone yelled at Mike. ...

We stopped and looked it up and found out that it is actually illegal to run without a shirt." "Sorry, Venetian people, we didn't know," the tourist added.

Fox News Digital reached out to the Instagram user for comment.

POPULAR CRUISE LINE’S BIKINI CRACKDOWN COULD SURPRISE PASSENGERS AT ISLAND PORTS The video, which was "liked" by nearly half a million Instagram users, drew criticism from some viewers.

"Everyone should be wearing a shirt," one person said.

"Clothes in public? Who would have thought," another chimed in.

Other viewers were surprised by the rule.

POPULAR VACATION HOT SPOTS SLAP LIMITS ON TOURIST RENTALS, DRIVING AND MORE TO PROTECT 'STUNNING' SPACES "Weird because of all the nude beaches and naked art that they have," an American user wrote.

"Are people expecting you to Google 'jogging laws Italy'? You don't know what you don't know," another viewer said.

Venice is one of many European vacation spots that have a number of lesser-known rules that could catch American tourists off guard, said Eric Bowman, editor-in-chief of Travel Pulse.