On the other hand, the famous case RoswellEdit refers to the alleged crash of an extraterrestrial spacecraft in Roswell (New Mexico), on July 10, 1947, an event that would have included the recovery of various corpses of ET beings. This event is considered the birth of modern ufology and has had significant repercussions on popular culture, to this day.
The abductions They refer to the alleged event in which a person is taken, against their will, aboard an extraterrestrial spacecraft, an experience that may include undergoing medical examinations of lesser or greater complexity. A known event in this matter is the alleged abduction of Betty and Barney Hill, between September 19 and 20, 1961.
…and supposed older antecedents
The theory of ancient aliens maintains that extraterrestrial beings have visited the Earth since time immemorial, being responsible, to a lesser or greater degree, for certain technological advances in some ancient cultures. A classic example is considering that the pyramids of Egypt could not have been built by the ancient Egyptians, and that they needed ET help.
…or, from another point of view, a clear example of how many contemporary individuals choose to discredit and distrust the immense achievements of human ingenuity in ancient cultures, simply because they did not have computers, calculators and the technology that seems so necessary today...
So how to explain the enormous abundance of these cases?
1st aspect to consider: influence of the media
Since the Kenneth Arnold case, and especially after the Roswell event, the media has been responsible for promoting, announcing, enhancing and generally validating the existence of the UFO phenomenon and its relationship with intelligent extraterrestrial beings. Examples of this can be seen continuously in books, movies, TV series and multiple “cases” around the world.
EN 
ES