Read the text and choose the best title for it.

Choose the correct option.

[The government's secrets|Creating a military aircraft|Extraterrestrial visitors|An effort to understand]

Project Blue Book was a United States Air Force programme established to investigate reports of UFOs from 1952 to 1969. Its primary goal was to assess whether UFO sightings posed any threat to national security. The project collected and analysed thousands of UFO reports. Investigators examined witness accounts, photographs, and radar data to determine the nature of the sightings. The project officially concluded that most UFO sightings could be attributed to natural phenomena, human-made objects, or psychological factors. However, a small percentage of sightings remained unexplained. Despite its closure in 1969, Project Blue Book has sparked ongoing interest and speculation about UFOs. Some believe that the project hid some information, while others argue it was a genuine attempt to understand the nature of UFO sightings.