The Overture to Cats is one of Andrew Lloyd Webber's best known orchestral numbers.

Green Eyes

The staging for the Overture starts in darkness with the lights flashing to punctuate the music.  As the music builds, anonymous Cats emerge into the dark with flashing green eyes on their heads.  As quickly as they appear, they disappear, leaving the audience wondering just what happened. Many productions have a central circular lighting rig, a "chandelier", that rises from the stage floor with cycling white lights, during the final section of the overture. 

In the original London production, the final moments of the overture saw the stage revolve into place, a jigsaw suddenly making sense as sight lines are resolved, and the chandelier rises from centre stage into place.

CATS- 1. Overture (Original London Version)

Audio - Overture