Area 51 border? (WireImage/Getty Images)A middle-aged man named Chuck Clark used to live in a trailer in Rachel, NV. The closest town to Area 51, Rachel is known as the terminus of the “Extraterrestrial Highway,” aka Nevada State Road 375. Chuck was intrigued by the local rumors and decided to investigate. He began asking questions, taking photographs and combing through any material he could find. One thing he was careful about—never crossing the boundary of the base. Marked by orange traffic-like cones every 50 feet or so, the border is known as the “line of death.” The ridges above the line bristle with advanced electronic sensors, listening devices and heavily armed guards. Signs warn that trespassers will be detained, arrested… or even shot.

One day Chuck stumbled on something in the ground and stopped to dig it up. He checked carefully to make sure he wasn’t on the Area 51 property itself. Chuck’s find turned out to be a highly sensitive “ground sensor,” designed to detect minute vibrations or movement on the surface. With the help of another researcher, a man named Joerg Arnu, Chuck found several of these sensors. He always checked to make sure they weren’t inside the boundary line. And he was careful to rebury them after he logged their location. Like many people, Chuck wondered why they would need sophisticated ground sensors so far from the base. What doesn’t the U.S. government want us to know about Area 51?

But soon, idle speculation turned to stark terror.

One day in late 2003, Chuck came home to find his trailer completely ransacked. His
written records, photos, computers, hard drives—and even personal effects—had been
taken. The phone was ringing urgently; it was the FBI. They demanded that Chuck come to a meeting in Las Vegas right away, which led him to believe the FBI was behind the raid. Las Vegas CBS affiliate, KLAS-TV, reported that "FBI agents have confirmed that a search warrant was served [the same night] on the home of a self-described military watchdog in the tiny town of Rachel, near the mysterious Area 51 military base." The warrant was sealed and the target's name not disclosed.

At the meeting, Chuck admitted to the FBI that he had dug up the early-warning devices, but denied he ever took one or interfered with their operation. In a quiet “arrangement,” Chuck agreed to stop his Area 51 research. He left Rachel, NV, and now lives in a
location he chooses not to reveal.

Local Las Vegas TV-news reporter named George Knapp has been on the Area 51 beat for two decades. Knapp believes there are a huge number of CIA dark projects at the base. He’s heard all the stories, from wild to mild. One thing Knapp knows for sure: every day at McCarren Las Vegas airport, a secret airline shuttles workers to and from Area 51. Known informally as “Lisa Airlines,” it loads and unloads passengers at unmarked gates. Questions directed to McCarren airport and local government officials go unanswered. The truth about Area 51 is kept hidden behind multiple layers of security and secrecy. But there may be some clues in plain sight—clues involving the SR71 and U-2 spy planes.