Close Encounter of the First Kind

Close encounter of the first kind: A sighting of an unidentified flying object (UFO).

Close encounter of the second kind: A sighting of a UFO which leaves physical evidence behind.

Close encounter of the third kind: Making contact with the occupants of the UFO.

Close encounter of the fourth kind: Going aboard the UFO.

Calling occupants of interplanetary craft
Calling occupants and interplanetary ultra-emissaries

We've been observing your Earth
And one night we'll make a contact with you
We are your friends     --John Woloschuk/Terry Draper (Klaatu)