What is civil twilight letters from the sky?

"Civil Twilight" is a South African-American rock band that was formed in 1996. "Letters from the Sky" is a single from their 2009 debut album "Civil Twilight". The song features a driving beat and ethereal guitar riffs, with lyrics that speak to a sense of longing and searching for something greater. The song has been featured in various TV shows and movies, including the trailer for the film "The Book of Eli" and the series finale of "Supernatural". "Letters from the Sky" was a commercial success, reaching the top 40 on the Billboard Alternative chart in the US and the top 10 in their native South Africa.