Greenwich Village resident Jon Barr has taken his YouTube followers all over the world through his travel vlog “Here Be Barr.” But on April 12, he took them to a scarier place: a hospital in Mexico City, where he found out he had testicular cancer.

The 32-year-old’s series usually focuses on traveling to non-touristy destinations on a budget. But in this vlog entry, he documented his journey with the cancer — starting with the very moment he realized something was amiss while wrapping up a segment in Mexico City.

“As I was saying ‘goodbye’ in the video, I just felt this shooting pain in my groin,” Barr, a former sports broadcaster tells The Post. “I had to sit down because it was really painful. I couldn’t walk for a few minutes. That’s when realized that something was really wrong.”

That first sign of trouble is captured clearly on film (above), when Barr’s brow furrows in pain. (Watch the full video here .)

At the urging of his girlfriend, who was traveling with him, Barr went to the hospital, where a radiologist pointed to a mass in one of his testicles. It was cancerous, the doctor told Barr.

He flew back to New York right away for treatment. There, he learned that the shooting pain he felt in Mexico City was actually a godsend — only half of testicular patients feel pain caused by tumors, his doctor told him.

“I was lucky that I had the symptom, because I wasn’t really checking in the shower,” he said.

In the weeks that followed, he waited with bated breath to learn if the cancer had spread. Thankfully, it didn’t — his form of cancer was less aggressive, and he was able to have the cancerous testicle removed without undergoing chemotherapy or radiation.

According to the American Cancer Society, the average age men get testicular cancer is 33. It’s a disease that largely affects young and middle-aged men — which also happen to be Barr’s main demographic on his YouTube channel.

Barr hopes that his experience will remind young men like himself to be better about performing self-exams. A handful of his regular viewers shared that they’ve checked themselves since seeing his video.

“For me, it was the most blindsided I’d ever felt,” Barr said. “You can go to the gym, eat well and still get cancer. It was a real reality check for me.”