WSVN -- Look up! On most days you see bright blue South Florida skies dotted with puffy white clouds, and then on some days you see this.
Fernando: "Very curious to start seeing it right over your head."
And what's going on in the sky appears to just be jet exhaust, but skeptics say it's something else.
David: "I think they're spraying chemicals."
Chemicals being sprayed? Criss-crossing the skies, lingering for hours and hours. Yes, say the believers.
Uri: "It's scary. It is very scary."
So much that instead of calling the jet exhaust contrails, some people are now calling these "chemtrails."
David: "They're using government planes that are unmarked, that are white. They're flying in military space, which is reserved strictly for the government."
David, Fernando and Uri, have each documented what they say is proof, plenty of photos.
Uri: "They've been out here over my house at Southwest Ranches doing the chemtrails."
Video they say show something is going on over our heads.
Randy Perini: "We just want to get to the bottom of this, find out what the truth is."
What fuels their fears that these are not normal jet exhaust trails is that the trails sometimes stay in place for hours instead of dissipating in minutes, and Fernando says some of his pictures show the trails are not from jet exhaust.
Fernando: "The smoke wasn't coming out of the engines. It was coming out of the tail section."
Another concern? The effect it's having on South Floridians.
David Black: "What we're going to do is just take a couple drops from your finger."
David Black is a health expert who says when chemtrails fill the sky over South Florida, his business picks up.
David Black: "People come in coughing and wheezing and have all kinds of health problems that can be prompted by that."
What is it? None of the people can be certain.
Uri: "I have no clue what's behind this. It can't be good, though because it's so hush-hush."
Fernando is convinced it's something sinister.
Fernando: "Whether they are for pollution to cause disease, for mind control, for environmental impact or even weather control. I want to know."
And the believers are popping up all over the world, posting what they call suspicious videos of chemtrails on the Internet, from Germany to Greece to London. With bold headlines reading, CHEMTRAILS - Clouds of Death," adding the chemicals being sprayed will soon cause the new holocaust.
David Black: "I hate to think of it because I can't imagine the government doing this, but I think they may be doing it to help control the population."
By now you are thinking, OK, some people have really gone off the deep end to think that the U.S. government would conduct experiments that could hurt people is ridiculous, or is it?
From the 1930s to the 1970s, the U.S. government experimented on 400 black Americans in the Tuskegee Experiment to see how their bodies reacted to untreated Syphilis.
In 1944, the American government sprayed 4,000 of their own servicemen with deadly mustard gas to see how they fared. The list goes on, and in each case, no one knew what the American government was doing.
Uri: "If there's nothing to it, why isn't someone coming forth and saying, 'Look, we're doing this for this reason, it's safe environmentally, it's safe health-wise.'"
So we went to the government to find out if anything is going on. First to the Federal Aviation Administration, which controls the skies.
Uri Katz: "Oh yeah, I've heard it. I mean, I know for a fact that it's not true."
The FAA says the lingering trails are a result of hot jet fumes in cold temperatures with no wind to dissipate them.
Jim Powell: "They're definitely not chemicals. It's just a heat reaction to the sub zero temperature to the air that's around it."
We then checked with the National Oceanic and Atmospheric Administration in Boulder, Colorado.
Dr. Joe Golden: "No evidence that I've seen or read or heard anywhere that there's any such thing going on."
But then we talked to Rosalind Peterson.
Rosalind Peterson: "So when they say, 'No, there's nothing going on,' I don't believe that."
Peterson is an environmental expert who testified before the United Nations about chemicals being released in our atmosphere. She is convinced governments are conducting experiments that are damaging the earth and the people on the planet.
Rosalind Peterson: "We had never seen anything like this in our county, in our history because I was born and raised there. It would have been noticed prior to this time, so we began to be suspicious that there was something different happening."
The government's reply, nothing is going on.
Rosalind Peterson: "No matter what you say, people are gonna still believe that something is going on."
And people will still believe these are chemtrails and not plain old jet exhaust. Maybe they are flat out wrong, or maybe there are are clouds of secrecy.