Tourists are strongly advised to consult an etiquette guide before visiting one of Thailand's revered temples. The lists of taboos is very long, and the country's ruling junta is strict.

Do not turn your back on a Buddha statue, the Bangkok Post cautions. Do not wear sleeveless tops to the temples, or show your knees. Even President Barack Obama had to remove his shoes when he toured the Wat Pho Royal Monastery a few years ago, lest he give offense.

Now let's put etiquette aside for a moment and introduce two men from California and their modestly popular Instagram page, “Traveling Butts.”

In case that concept also requires elaboration: Joseph and Travis Dasilva travel to scenic places around the world and post photos of their naked butts.

The Dasilvas, both 38, were in Bangkok last week to celebrate their first anniversary, their house sitter in San Diego told NBC 7.

There, they encountered the towering majesty of Wat Arun — the Temple of the Dawn, whose central spire is said to symbolize a mountain at the center of the universe.

The men wore tank tops and jean shorts, and did this:

Posted by Scott Poston on Wednesday, November 29, 2017

“They didn't know it was a temple,” the house sitter told NBC 7. “It's just like a building.”

Much of Thailand didn't see it the way. Certainly not Sudarat Wajanasiri, who shared the Dasilvas' photo on Facebook over the weekend, adding: “I got no words RIP them.”

From there the images spread across the country.

One commenter made an earnest attempt to figure out what would compel two men to moon a holy site, discovering that traveling butt photos are something of a cultural tradition in Western countries and cautioning that the Americans may not have meant to give offense.

But the prevailing Facebook sentiment was that the Dasilvas should be thrown out of Thailand or thrown in jail, possibly both.

Federal police apparently agreed.

Thai immigration officials put the men on a watch list after seeing the photo, according to BBC. The “Traveling Butts” account was deleted from Instagram, and an unverified screenshot of a message from Joseph Dasilva's personal Facebook page offers a semi-apology:

“We deleted the pictures as soon as we got the word that this was not well received by the Thai people. Hope that makes things better.”

Things did not get better. Police detained both men at a Bangkok airport on Tuesday, as they tried to leave the country, BBC reported.

They face a charge of public nudity, which carries a $150 fine and possible permanent banishment from the country. But a police colonel told the Straits Times that he has asked a court to prosecute the men on pornography charges, which could put them in jail for up to five years.

A San Diego city commissioner told San Diego Gay & Lesbian News that she had reached out to the U.S. government to help the men, who could not be reached by The Washington Post.

Their house sitter, Nyx Blue, told NBC 7 that they were trying to find a lawyer in Thailand, and had no idea if or when the Traveling Butts would come home.

“All over a simple, dramatic thing,” Blue said. “A simple butt!”

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