What are now sometimes called "disco balls" were first widely used in nightclubs in the 1920s. They were already in existence and use before then, appearing in a description of a ballroom dance in 1897 in Boston.[1]. An early example can be seen in the nightclub sequence of Berlin: Die Sinfonie der Großstadt, a German silent film from 1927. In the 1960s, '70s and '80s, these devices were a standard piece of equipment in discotheques, and by the end of the 20th century, the name "disco ball" had grown quite popular.[citation needed] - Pink Floyd used a glitter ball on their 1987 and 1994 world tours. The glitter ball used on the 1987 tour was somewhat larger than normal but nowhere near as large as the glitter ball used on the 1994 tour. This particular glitter ball is one of the largest in the world. 4.9 metres in diameter, it rises to a height of 21.3 metres before opening to a width of 7.3 metres, revealing a 12 kilowatt Phobeus HMI lamp.[2] Both can be seen on the video of each tour: "Delicate Sound of Thunder and "P*U*L*S*E" during the song "Comfortably Numb". Madonna used a 2-ton glitter ball that was embellished by 2 million dollars' worth of Swarovski crystals for her Confessions Tour in 2006. [3] The world's largest disco ball can be found on the promenade in Blackpool, UK. [4] . Disco Ball: Although around since the 1920s and the staple of most dance halls, this mirrored ball was reborn during the Disco era and has forever remained linked to Disco. These balls are made up of hundreds of small mirror tiles and were hung from a hook attached to a rotating motor. When a spotlight is aimed at this revolving mirrored surface it floods the dance floor with moving reflections that add to the ambiance. No Disco or Disco themed party is complete without a Disco ball... the larger the diameter of a Disco ball the better.