Since 1986, a mysterious phenomenon has been reported all over the world. Signs and crosses of light have appeared as if projected on facades but also shimmering in the air like holograms. The appearances began in the USA, spreading to many other countries. With no identifiable source, a brightly lit cross or other shape suddenly appears from one moment to the next, visible even when the sun is shining but never at night. No one has yet been able to identify the source of these mysterious source lights.

Excerpt from Mysteries of the World, by Herbert Genzmer and Ulrich Hellenbrand.