Delerium

Delerium is a Canadian musical group that formed in 1987, originally as a side project of the influential industrial music act Front Line Assembly. Throughout the band’s history, their musical style has encompassed a broad range, including dark ethereal ambient trance, voiceless industrial soundscapes, and electronic pop music. They are best known for their worldwide hit "Silence", which features vocals from Sarah McLachlan. The song has been hailed as one of the greatest trance songs of all time, over a decade after its initial release.

source: Wikipedia