Impressive:
Cagna Illuminations
This Cathedral of light was displayed in the recent 2012 Light Festival in Ghent, Belgium with 55,000 LED lights covering this immense structure. . The entrance was through a giant colonnade, 28 meters high, of light and effervescent colours. The whole structure, despite its size, still only consumed 20Kwatt/h of electricity.
(Source: catrinastewart)