The bermuda triangle could be a portal to aliens being underwater and how that one plane mysteriously dissapreaded around that location.

Aliens kidnapping people and how some people have stories they've seen with proof.

I'm pretty shure they are underwater since we can't leave earth and since they are advance they've probably reached the bottom of the ocean with their technology.

Humanity has been contemplating the possibility of life on other planets for thousands of years.

Aliens are intelligent enough to want to build a spaceship, or a radio telescope something complicated,You'd need to know a lot about physics and mathematics. You'd have to have the ability to develop scientific theories and to collaborate. 

Humanity's ideas about aliens have been evolving for years 

For example, one man had been driving along a winding road through the White Mountains, when he was snatched by a group of extraterrestrials, they said. He said that when he was kidnapped, he had been examined by these strange beings in an uncomfortable way, and he said that they boarded a flying saucer-style spacecraft.