Before Area 51 occupied the land currently housing it, there was occupied by the Groome Lead Mines Limited. This English mining company mined silver and lead around what we know today as Groom Lake. (Can you guess how the lake got its name?)
Groome Lead Mines Limited was a key player in the mining industry during the 1870s.
A Fateful Memo
In 1974, William Colby, The director of the CIA at the time, got a panic-inducing memo. According to the memo, astronauts on the Skylab space station took pictures of a location that is sensitive to the CIA.
Obviously, the CIA wanted the pictures classified right away for national security reasons. The Agency debated over the issue with Skylab at length, in what became known as the "Skylab Incident", but no one knows the ultimate results of the debate. We'd like to see the pictures and decide for ourselves if you don't mind.
Putting Two and Two Together
Dwayne A. Day is a space historian. (Apparently, it's a thing.) He took a special interest in the mysterious pictures taken from Skylab space station. The debate around the subject never mentions Area 51 by name, but he was convinced that this is what's shown in the astronauts' pictures. At the time of the Skylab Incident, the government didn't even confirm that Area 51 even existed!
Day ended up publishing an article titled "Astronauts and Area 51: the Skylab Incident" in an online magazine called "The Space Review" in 2006. Such determination!
Just Like Monopoly
The mines around modern-day Area 51 were active for nearly a hundred years, during which the ownership changed hands. After Groome Lead Mines Limited, the next owners were J. B. Osborne and his partners.
Apart from a temporary shut-down in 1918, the mines had a pretty steady run. They closed permanently in the 1950s, making way for Area 51 and a plethora of conspiracy theories.
"Independence Day"
In 1996, the sci-fi film "Independence Day" came out and became a pop-culture staple. The film triggered renewed interest in Area 51 and the alien theories circling it.
In the film, the White House is destroyed by ill-intended alien invaders, and the good guys use Area 51 as their new home base. Not exactly a documentary, but still thoroughly entertaining.