New Delhi, April 4 -- UFOs, or the notion of them, have been around a long time. Here's a look at how the various iterations of the subject - from government investigations to sightings to movies and TV - have unfolded since World War II:

1947: First widely reported UFO sighting in US

On June 24, private pilot Kenneth A. Arnold reports seeing nine objects flying near Mount Rainier in Washington state. His was the first widely reported UFO sighting in this country and set off a wave of other reported sightings. On July 2, A ranch foreman checking on sheep finds strange debris spread over a prairie near Roswell, New Mexico. Authorities initially say the material is from a flying disc, but later say it is from a weather balloon.

1948: Off...