Passage: Def Leppard's debut album, On Through the Night, was released on 14 March 1980. Although the album hit the Top 15 in the UK, many early fans were turned off by the perception that the band was trying too hard to appeal to American audiences by recording songs such as "Hello America" and touring more in the US (supporting Pat Travers, AC/DC, and Ted Nugent); a performance at the Reading Festival in August was marred when audience members expressed their displeasure by pelting the band with beer cans and bottles filled with urine. This incident was partially blamed on a cover story in Sounds music newspaper by the journalist Geoff Barton titled, "Has the Leppard changed its spots?", accusing the band of selling out to the American market. In a documentary on the band recorded for BBC 2, Barton recalls feelings of guilt over the story and having a "stand-up row" with the band's manager, Mensch, backstage at the show. In the documentary series Metal Evolution, Joe Elliott says that the media had exaggerated the event and all bands on the day had experienced 'abuse' from the crowd.

Question: What was Def Leppard's first album called?
On Through the Night