CASTLE OF GLASS is the fourth official single from Linkin Park's fifth album LIVING THINGS. The track was released internationally on November 12th, 2012 as a digital track, with all proceeds benefiting the Help for Heroes charity in the UK. CASTLE OF GLASS was also released as a physical CD single on December 7th, 2012, pushed back from its original November 23rd, 2012 date for unknown reasons. The two-track features the studio version of CASTLE OF GLASS along with LOST IN THE ECHO (Killsonik Remix).

CASTLE OF GLASS is the third song from LIVING THINGS to have a music video. Shot and released as a joint project between Linkin Park and Medal of Honor: Warfighter, the video incorporates both live performance footage, gameplay and live action inspired by EA and Danger Close's first-person shooter franchise.