Which song by Mariah Carey and Boyz II Men spent 16 weeks at number one?

The Mariah Carey and Boyz II Men song that spent 16 weeks at number one was "One Sweet Day." Released in November 1995, the emotional ballad became the second single from Carey's album Daydream and one of the defining collaborations of the 1990s.

Carey and Boyz II Men wrote the song with Walter Afanasieff and the members of Boyz II Men. Its lyrics were shaped by personal experiences of loss and by the AIDS epidemic, giving the song a memorial quality rather than a conventional romantic theme. The singers recorded the collaboration after being introduced through their shared label connections and musical colleagues.

"One Sweet Day" debuted at number one on the Billboard Hot 100 and remained there for 16 consecutive weeks, from December 2, 1995, through March 16, 1996. It held the chart's longevity record for more than two decades. "We Belong Together" was another Carey hit, while "End of the Road" and "I'll Make Love to You" were separate Boyz II Men chart-toppers.