Cheers filled a convention center in Pittsburgh as President Trump touted his long-promised border wall during a Wednesday event. But then, some in the crowd started to laugh. Others shook their heads and exchanged looks.

That’s because Trump, in the middle of rattling off states the proposed barrier would run through, said, “We’re building a wall in Colorado.” He added, “We’re building a beautiful wall. A big one that really works, that you can’t get over, that you can’t get under.”

The brief, and incorrect, utterance instantly sparked widespread confusion and derision with many politicians and public figures pointing out that Colorado — located hundreds of miles north of Mexico — is not a border state.

“Well this is awkward …” tweeted Colorado Gov. Jared Polis (D). “Good thing Colorado now offers free full day kindergarten so our kids can learn basic geography.”

By late Wednesday, the gaffe was a top trending moment on Twitter and the reaction had grown so strong that even Trump appeared to notice. At 12:20 a.m. on Thursday, the president fired off a tweet in an attempt to clarify his comments, writing that he had “kiddingly” brought up Colorado to suggest that non-border states could also benefit from the wall.

That convoluted 47-word missive seemed to only fuel more mockery, though.

Trump’s original head-scratching remarks about the border wall came roughly 40 minutes into his hour-long speech Wednesday afternoon as he addressed the crowd at an energy conference in Pittsburgh.

The president had just finished boasting about his administration’s tax cuts when he abruptly pivoted to predicting that he would win New Mexico, which hasn’t gone Republican since 2004, according to Vox.

“You know why we’re going to win New Mexico? Because they want safety on their border and they didn’t have it,” Trump said, drawing applause that only became louder as he declared that the wall would be built there, as well in Texas — and Colorado.

“We’re not building a wall in Kansas,” he continued, referencing Colorado’s eastern neighbor, “but they get the benefit of the walls that we just mentioned.”

At first, people had questions.

“Ummm, Colorado? Is Wyoming invading?” one person asked on Twitter.

“Is that to keep out the Nebraskans or those pesky folks from Wyoming?” another wondered.

It didn’t take long, however, for the bewilderment to transform into ridicule, as leaders joined social media users to mock the president.

Sen. Patrick J. Leahy (D-Vt.) got in on the roasting by sharing a Sharpie-edited map of the United States, a reference to Trump’s infamous Hurricane Dorian debacle. In September, Trump came under fire for displaying a chart forecasting the path of the hurricane that had been altered using black marker.

Sen. Michael F. Bennet, a Democratic presidential candidate from Colorado, and the state’s former governor John Hickenlooper also hit back at Trump.

In a tweet tagging Democrats from New Mexico, Hickenlooper wrote, “Do one of you want to break it to @realDonaldTrump that Colorado’s border is with New Mexico, not Mexico … or should I?”

On CNN Wednesday night, host Don Lemon echoed Hickenlooper, stressing that the two locations are “not the same thing.”

“Colorado?” Lemon asked incredulously after he got his laughter under control. “Who’s going to pay for that one?”

Meanwhile, Twitter was rife with biting commentary.

“I took my SATs on ecstasy, and even then I knew where Colorado was located,” comedian Chelsea Handler tweeted.

Some implied that Trump’s gaffe could be the product of knowledge gap.

“The geography department at Trump University was severely underfunded,” a Twitter user wrote.

Perhaps, one person suggested, the Colorado remark was intended as a distraction. Earlier in the day, Trump faced criticism for tweeting that “Never Trumper Republicans” are “human scum.” Republican House members also stormed a closed-door meeting on Wednesday in a secure facility on Capitol Hill, delaying the testimony of an impeachment witness.