World Contact Day
March 15, 1953 - This day was declared the first World Contact Day by an organization called the International Flying Saucer Bureau. A call was sent out to all its members with directions for sending a collective telepathic greeting to visitors from outer space.
The message began with "Calling all occupants of interplanetary craft!" The hope was that this day would become an annual tradition and that an alien intelligence would hear and accept the invitation to make contact.
In 1976 the band Klaatu released a song, Calling Occupants Of Interplanetary Craft, which was inspired by the event.
The Carpenters released their own version the following year: