"Storm Area 51", otherwise known as "Storm Area 51, They Can't Stop All of Us", was an event that took place on September 20th, 2019.
The whole thing was the brainchild of California student Matty Roberts who came up with the idea of organizing a collective effort to 'storm' the secretive facility after listening to a podcast interview with Bob Lazar - a man who claimed to have worked with reverse-engineered UFO technology at the base.
Roberts posted up a somewhat tongue-in-cheek event listing on Facebook and didn't really expect it to gain much interest, but when the post inexplicably went viral a few days later, he ended up with several million people registering their interest.
"I posted it on like June 27th and it was kind of a joke," he said at the time. "And then it waited for like three days, like 40 people, and then it just completely took off, out of nowhere. It's pretty wild."
In the end, Roberts himself never actually went to Area 51 on September 20th (instead opting to attend an alien-themed party in Las Vegas), but at least 150 people did reach the two perimeter gates.
Ultimately, though, none of them were able to penetrate any deeper into the restricted zone.
The event itself gained so much attention on social media that two music festivals ended up being organized to coincide with it.
The first, known as Alienstock, took place in the nearby town of Rachel, while the second - known as Storm Area 51 Basecamp - took place in Hiko (although the latter was canceled early due to low attendance).
Between them, they attracted around 1,500 people on the day, far less than initially planned.