The Most Beautiful Moment in Life, Pt. 1 (Hangul: 화양연화 pt.1; Hanja: 花樣年華 pt.1; RR: Hwayangyeonhwa pt.1) is the third extended play by South Korean boy bandBTS. The album was released on April 29, 2015 by Big Hit Entertainment. It is available in two versions and contains nine tracks, with "I Need U" as the lead single and "Dope (쩔어)" as a promoted follow-up single.
On April 6, 2015, BTS announced their comeback date for April 29, and revealed that all members participated in writing songs for the album. On April 17, an animated comeback trailer was uploaded on Big Hit Entertainment's official YouTube channel, which featured the album's intro track performed by Suga. On April 19, Big Hit Entertainment announced the title of the album, and the first set of member concept photos was posted on their official Twitter account. Along with the reveal of the second set of concept photos, it was stated that two different cover design versions of the album would be released, Pink and White. The album would also include a 120-page photobook and a random photo card. Big Hit Entertainment released the first music video teaser for the album's lead single "I Need U" on April 23. On April 26, the album's track list was revealed, and an album preview was uploaded on Big Hit Entertainment's YouTube channel. Two of the album's tracks, "Boyz with Fun" and "Converse High," had previously been previewed at the 2015 BTS Live Trilogy Episode I: BTS Begins concert held in Seoul on March 29.
On June 14, BTS posted concept photos for the follow-up promotion track "Dope (쩔어)" through their official Facebook page, captioned with the opening line of the song: “Welcome, first time with BTS?"
The music video for "I Need U" was released on April 30, 2015. The video was revealed to have been edited to lower the 19+ rating down to a 15+ rating, as it carefully portrays each band members' stories representing troubled youth. On May 10, the uncut, original 19+ version of the music video was released, which includes nearly two minutes of extended scenes and contains darker themes and more graphic imagery than the previous video. Both versions of the "I Need U" music videos were produced and directed by Lumpens.
On June 24, Big Hit Entertainment released the music video for "Dope (쩔어)" on YouTube. It features each of the members dressed up to represent various occupations, such as a police officer or office worker, while dancing fast-paced choreography. The dance was choreographed by Keone Madrid, and the music video was produced and directed by GDW.
On April 29, 2015, prior to the release of the "I Need U" music video at midnight, BTS broadcast a live comeback special  called "I NEED U, BTS ON AIR" through Naver Starcast. On April 30, BTS held their first comeback stage performance on Mnet’s M Countdown. Two tracks from the album, "Boyz with Fun" and "Converse High", were deemed unfit for broadcast by KBS due to lyrics containing swears and brand names, such as Converse, Chanel, and Alexander McQueen. The latter track was also deemed unfit for broadcast by MBC. However, the group went on to successfully promote across multiple channels and various programs, including on KBS, MBC, SBS, and Arirang TV. BTS wrapped up promotions for "I Need U" with the last performance held on the May 31 broadcast of SBS Inkigayo.
On June 13, BTS announced their plans to hold follow-up promotions on music show programs with the track "Dope (쩔어)", and subsequently made their comeback on the June 25 broadcast of M Countdown. Promotions for "Dope" concluded on July 5 with their final performance on Inkigayo.
Immediately after the release of the album, "I Need U" became the top trending search term on Korean portal sites and ranked number one on various real-time music charts, including Soribada, Genie, and Daum Music. The song also managed to crack the top 10 on Melon, Bugs, and Naver Music's real-time music charts. The music video for "I Need U" reached one million views in 16 hours, while the "Dope (쩔어)" music video garnered one million views in less than 15 hours—the fastest record for any BTS music video at the time. "Dope" gained considerable attention internationally as it became the subject of numerous reaction videos on YouTube, the most noteworthy being from the Fine Brothers channel. "Dope" went on to become the group's first music video to surpass 100 million views on YouTube, making BTS the first K-pop group outside the "big three" Korean entertainment agencies (SM, YG, and JYP) to achieve this feat.
On May 5, 2015, "I Need U" won number one on the South Korean music program SBS MTV's The Show, which marked their first music show win since their debut. The group went on to win an additional award on The Show, one on MBC's Show Champion, one on Mnet's M Countdown, and one on KBS's Music Bank, for a total of five awards. In South Korea, the single "I Need U" debuted at number five on both the Gaon Weekly Digital Chart and the Gaon Download Chart with 93,790 digital units sold in its first week. The single went on to accumulate over 850,000 digital downloads. Additionally, the album debuted at number two on the Gaon Weekly Album Chart and rose to number one the following week. It peaked at number two on the Gaon Monthly Album Chart in May. In China, BTS ranked number one for two consecutive weeks on the Gaon Weibo Chart, a weekly rank of the top 10 most popular Korean artists based on data gathered from China’s most popular social media platform, Weibo. In Japan, the album debuted at number 24 on the Oricon Weekly Album Chart and number 45 on the Oricon Monthly Album Chart.The Most Beautiful Moment in Life, Part 1 was the sixth best-selling album in South Korea in 2015 with sales over 200,000 copies.
BTS charted a total of six songs on the Billboard World Digital Songs Chart, with "I Need U" ranked highest at number four, followed by "Dope" (number 11), "Hold Me Tight" (number 12), "Boyz with Fun" (number 13), "Converse High" (number 15), and "Outro: Love is Not Over" (number 25). On July 11, after having completed follow-up promotions, "Dope" peaked at number three on the World Digital Songs chart. The album also debuted at number two on the Billboard World Albums Chart, peaked at number six on the Billboard Top Heatseekers Chart, and entered the Billboard Independent Albums Chart for the first time at number 20, all of which were the highest for any BTS album at the time.The Most Beautiful Moment in Life, Part 1 was named by Fuse as one of the "27 Best Albums of 2015 So Far", with BTS being the only Korean artist to be recognized on the list.