Why doesn't the governments of the world admit that there are crafts from outside our world visiting Earth?

They are all tight-lipped, citing threats to National Security. Even some of the Presidents we had who vowed to find out the truth will not say. Was Kennedy going to blab? When you have airline pilots and military jets seeing, and taking videos of them you gotta wonder. Just look at all our devices can do these days. How did we get that technology in just 30 years? Would revealing the truth really screw up the world, or just those rich suckers who control it? What do you think?

Mayan artifacts
Mayan artifacts
Ancient astronaut?
Ancient astronaut?
Why doesnt the governments of the world admit that there are crafts from outside our world visiting Earth?
Dude in old painting checking out ufo
Dude in old painting checking out ufo
Old carving showing sun and 9 planets
Old carving showing sun and 9 planets
old carving with helicopter and other vehicles
old carving with helicopter and other vehicles
The Vimana of India
The Vimana of India
Old Mexican Artifact
Old Mexican Artifact
Shit! Whose idea was it to bring these beasts here to start the Eco-system?
Shit! Whose idea was it to bring these beasts here to start the Eco-system?
Pyramid construction - too much accuracy for man even today
Pyramid construction - too much accuracy for man even today
Why doesn't the governments of the world admit that there are crafts from outside our world visiting Earth?
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