Under the Iron Sea is the second studio album by the English rock band Keane, released on 12 June 2006. During its first week on sale in the UK, the album went to #1, selling 222,297 copies according to figures from the Official Chart Company. In the United States, the album went to #4 on the Billboard 200, selling 75,000 copies in its first week there. Since 22 January 2006, the album has sold over 3,000,000 copies worldwide.

Keane singer Tom ­Chaplin bares his emotions and confronts his demons on The Wave, a solo debut that is both vulnerable and victorious. He is honestly blunt when describing lapses and relapses, while seeking salvation through acceptance. Hardened Heart finds him at his rawest – "How I wish I was not hurting everyone I know" – and also his most hopeful: "I know that my hardened heart is beating still."