While Top 40 mainstays such as Taylor Swift go through their album rollouts and release single after single every year, from 2014-2015 other artists came back to the realm of music, releasing new singles in hopes of reinvigorating their careers.

Some pop stars don’t quite connect to the audience, such as Fergie’s failed attempt at making a comeback in 2014, while others soar with flying colors, such as Miley Cyrus’ 2013 dominance with her hit single “We Can’t Stop”, along with her new style. However, in 2015, two of pop music’s biggest acts made waves with some of the best comebacks in recent memory—Justin Bieber and Adele.

After releasing his last official album, Believe, a number one album in 2012, Justin Bieber went on a downward spiral. This spiral led to a string of legal troubles, from accusations of vandalism and reckless driving to an eventual arrest in 2014, causing fans and the general public to quickly turn on him.

In 2015, though, things started looking up for the Biebs; he publicly apologized to the world through multiple appearances on The Ellen DeGeneres Show and his Comedy Central “roast,” where other celebrities deliberately made fun of him to his face. Having rehabilitated his public image, Bieber was ready to return to the studio. The release of “Where Are Ü Now” by Jack Ü, a heavily processed dance single with an infectious hook and distorted vocals, brought him back to the top of the charts. The song eventually went Top 10 on the Billboard Hot 100— his first in three years.

Bieber’s success didn’t stop at “Where Are Ü Now,” as he followed it up with a single of his own without any features. “What Do You Mean?” debuted at number one on the Hot 100, making him the youngest artist to do so. In addition, he performed the song at the VMA’s and received critical acclaim for the performance and his tears of joy on stage. Later, he told Jimmy Fallon was because he was grateful for his fans’ support during a difficult three years.

In November, the world’s latest epidemic of “Bieber Fever” kicked into overdrive when his new album, Purpose, was released. Purpose beat out One Direction’s latest album for the number one position, and spawned two more top five hits, “Sorry” and “Love Yourself.” This solidified his comeback to pop music with a new sound and improved public image.

“I love the way Justin Bieber expressed his feelings in his new music,” senior Carly Soucie said. “I never used to listen to his music but it has come a long way.”

Although Justin Bieber’s comeback in 2015 was groundbreaking, it doesn’t seem to compare to Adele’s global dominance this year.

In October, commercials aired during an episode of The X Factor in the U.K. put Adele fans, craving a follow-up to her diamond-selling sophomore record 21, into a frenzy.

Already having named the album 25, Adele also teased it earlier in 2014 in a tweet hinting  that the album would be out by the end of the year. When the album wasn’t released, rumors ran rampant with guesses as to when the album would drop, and with almost no time to prepare, “Hello,” the lead single, dropped October 23 with an accompanying music video. The song broke countless records, becoming the most viewed music video in 24 hours on Vevo and the most downloaded song in one week with over a million purchases.

Adele’s reign didn’t stop there. 25 broke tons of records as well, including most copies sold of an album sold in one week, an astonishing 3.38 million. According to Billboard, 25 was also the first album to sell a million copies in two separate weeks.

“Adele has once again found a way to so eloquently pinpoint some of our greatest struggles [on her new album],” senior Laine Thelian said. “Her words are applicable in so many situations, including our transition into adulthood, as many of us are facing the reality of going off to college in less than a year.”

All in all, Justin Bieber and Adele returned to music in 2015 with some of the biggest comebacks in recent memory, breaking various records and setting new standards for what other artists will need to do in order to make their comebacks stand out.

“I’ve always been one for a good comeback, and this year Adele and Justin Bieber did just that,” senior Michaela Fader said. “Their new music is better than ever.”