LAS VEGAS (AP) - No one knows what to expect, but people are preparing for "Storm Area 51" in the remote Nevada desert.

Visitors descending on the tiny towns of Rachel and Hiko near the once-secret military research site are from Earth, not outer space.

Area 51's secrecy fuels fascination about UFOs and conspiracy theories. An internet joke inviting people to "see them aliens" has given rise to festivals this week.

The military has warned people not to approach the protected site.

Neighbors, elected officials and experts say the craze might become a cultural marker, a dud or something in between.

Events include an "Area 51 Basecamp" in Hiko featuring music, speakers and movies and dueling "Alienstock" festivals. One is Thursday through Sunday in Rachel, and another is Thursday in Las Vegas.