Here's the official site of Deutsche Grammophon's 20/21 series.
And here's the Spotify playlist that collected all the 20/21 albums in one place: 20/21.(574 tracks, 2.1 days)
I also put in another Luigi Nono album at the end of the playlist, it's from DG's 20th Century Classics series, features the beautiful "....Sofferte onde serene....for piano and magnetic tape" played by Pollini. Below is a well made video of Berio's Sinfonia, one of the many modern masterpieces that gorgeously represented in this splendid series. It's so refreshing to see Sir Simon Rattle in a suit, not that fluffy turtleneck;)
Two more link for this wonderful piece of work. The wiki page, which lists all the works Berio quoted in the 3rd movement, and a very informative introduction in the Modern World. Welcome to post any interesting links that you found on the composers and works in this series:)