Adele released her second studio album, 21, on 24 January 2011 in the UK and 22 February in the US. She said that the album was inspired by the break-up with her former partner. The album's sound is described as classic and contemporary country and roots music. The change in sound from her first album was the result of her bus driver playing contemporary music from Nashville when she was touring the American South, and the title reflected the growth she had experienced in the prior two years. Adele told Spin Magazine: "It was really exciting for me because I never grew up around [that music]." 21 hit number 1 in 30 countries, including the UK and the US.An emotional performance of "Someone Like You" at the 2011 Brit Awards on 15 February propelled the song to number one in the UK. Her first album, 19, re-entered the UK album chart alongside 21, while first and second singles "Rolling in the Deep" and "Someone Like You" were in the top 5 of the UK singles chart, making Adele the first living artist to achieve the feat of two top-five hits in both the Official Singles Chart and the Official Albums Chart simultaneously since The Beatles in 1964. Both songs topped the charts in multiple markets and broke numerous sales performance records. Following her performance of "Someone Like You" at the 2011 MTV Video Music Awards, it became Adele's second number-one single on the Billboard Hot 100. By December 2011, 21 sold over 3.4 million copies in the UK, and became the biggest-selling album of the 21st century, overtaking Amy Winehouse's Back to Black, with Adele becoming the first artist ever to sell three million albums in the UK in one calendar year. "Set Fire to the Rain" became Adele's third number one single on the Billboard Hot 100, as Adele became the first artist ever to have an album, 21, hold the number-one position on the Billboard 200 concurrently with three number one singles. Moreover, 21 had the most weeks on the Billboard 200 chart of any album by a woman.To promote the album, Adele embarked upon the "Adele Live" tour, which sold out its North American leg. In October 2011, Adele was forced to cancel two tours because of a vocal-cord haemorrhage. She released a statement saying she needed an extended period of rest to avoid permanent damage to her voice. In the first week of November 2011 Steven M. Zeitels, director of the Center for Laryngeal Surgery and Voice Rehabilitation at the Massachusetts General Hospital in Boston, performed laser microsurgery on Adele's vocal cords to remove a benign polyp. A recording of her tour, Live at the Royal Albert Hall, was released in November 2011, debuting at number one in the US with 96,000 copies sold, the highest one-week tally for a music DVD in four years, becoming the best-selling music DVD of 2011. Adele is the first artist in Nielsen SoundScan history to have the year's number-one album (21), number-one single ("Rolling in the Deep"), and number-one music video (Live at the Royal Albert Hall). At the 2011 American Music Awards on 20 November, Adele won three awards; Favorite Pop/Rock Female Artist, Favorite Adult Contemporary Artist, and Favorite Pop/Rock Album for 21. On 9 December, Billboard named Adele Artist of the Year, Billboard 200 Album of the Year (21), and the Billboard Hot 100 Song of the Year ("Rolling in the Deep"), becoming the first woman ever to top all three categories.

Question: Who inspired Adele's second studio album?
Answer: break-up with her former partner