Iran is home to some of the world’s most spectacular architecture.

In the Golestan Palace in Tehran, ornate chandeliers hang from the high ceilings of lavish halls. In the ruins of the ancient city of Persepolis, the remains of buildings are so majestic that the United Nations’ cultural body, UNESCO, has declared them “among the world’s greatest archaeological sites, among those which have no equivalent and which bear witness of a unique quality to a most ancient civilization.”

Nationwide, lush vegetation surrounds stunning fountains, pools and courtyards, honoring the distinct Persian gardening tradition. Centuries-old mosaics line the walls of the country’s most beautiful mosques.

So when President Trump threatened via Twitter last weekend that if Iran struck American targets, the United States would retaliate with strikes against sites “important to Iran & the Iranian culture,” fears emerged that thousands of years of history could be erased in a single U.S. attack.

On Twitter, Iranians and others who have visited Iran recoiled at Trump’s threats. They shared photos of their most treasured historic landmarks, including images of some of the 22 cultural sites protected by UNESCO.

Holly Dagres, a nonresident fellow at the Atlantic Council who specializes in Iran, was born in the United States to an Iranian mother and moved to Iran as a teenager. Her family is from Tehran, but she said she tweeted photos of Isfahan, a city about 250 miles south of the capital, because it’s “where I fell in love with Iran.”

“It was there that I really understood what being Iranian was all about,” she said. “Our country was a lot more than what was being broadcast in the media or headlines. We were a country of poets and not just Islamic history but ancient Persian history, and we had so much to offer the world.”

In the days following Trump’s tweets, outrage mounted over the suggestion that the United States would attack cultural sites. Critics compared Trump’s comments to behavior by militant groups such as the Taliban, which notoriously destroyed two massive 6th-century Buddha statues in Afghanistan’s Bamian province, leaving gaping holes in the side of the cliff where they once stood, or the Islamic State, which destroyed parts of the ancient Syrian city of Palmyra, including an amphitheater where the group carried out public executions.

But Trump on Sunday justified his comments threatening cultural sites, even as the outcry grew.

“They’re allowed to kill our people. They’re allowed to torture and maim our people,” he told reporters. “They’re allowed to use roadside bombs and blow up our people. And we’re not allowed to touch their cultural sites? It doesn’t work that way.”

On Monday, Iran’s ambassador to UNESCO met with the body’s director general, who released a statement noting that the United States and Iran are signatories to international conventions that bar them from attacking cultural heritage sites.

And on Tuesday, responding to questions about whether Trump would in fact target cultural sites in Iran, Secretary of State Mike Pompeo said the United States would abide by international laws. But he added that Iranian leaders, not Trump, are the ones threatening Iran’s culture.

“Let me tell you who has done damage to the Persian culture. It’s not the United States of America, it’s the ayatollah,” he said, referring to Iran’s supreme leader, Ayatollah Ali Khamenei. “Persian culture is rich and steeped in history and intellect, and they’ve denied the capacity for that culture to continue."

Matthew Canepa, a professor of art history and ancient Iranian archaeology at the University of California at Irvine, said that claim is “completely baseless and ignorant.”

He said that although Iran has “always had a sort of strange relationship with its past,” in recent years, there’s been “even more of an appreciation and use of cultural sites.”

“Persepolis is a big tourist draw. … They’re doing their best to preserve it,” Canepa said, referring to the ancient city that withstood myriad political changes over the course of Iranian history. “It’s just tragic to think that something like that which has endured since 515 B.C. could be targeted.”

And although many ancient archaeological sites were destroyed or looted after years of war in Iraq and Syria, Canepa said Iran has done one of the “best jobs of preserving the Middle Eastern archaeological record.”

Trump later seemed to walk back on his earlier announcement he planned to target cultural sites, saying to reporters in the Oval Office Tuesday, "We are, according to various laws, supposed to be very careful with their cultural heritage. And you know what, if that’s what the law is, I like to obey the law.”

Pompeo also tweeted Tuesday that Iranian leaders have damaged Persian culture by “disrespecting Cyrus and holidays like Nowruz, prohibiting dancing, and putting an end to religious tolerance.”

As The Washington Post’s Ishaan Tharoor has noted before, the Trump administration has an unusual affinity for Cyrus the Great, the ancient Persian emperor who founded Pasargadae, the first capital of the Achaemenid Empire. The remains of the city are in modern-day Fars province in Iran and were designated a UNESCO World Heritage Site in 2004.

Last year, Pompeo tweeted a commemoration to Cyrus, saying that Oct. 29 marked the anniversary of the day Cyrus the Great “entered Babylon and freed the Jewish people from captivity.”

“His respect for human rights and religious freedom inspired America’s founding fathers,” Pompeo wrote. “The U.S. stands with the Iranian people, who are blocked by the regime from celebrating his legacy.”