Which recurring segment debuted in 1998 as Elmo's 15-minute feature?

Elmo's World debuted in 1998 as Sesame Street's 15-minute feature devoted to Elmo. It was placed at the end of each episode and presented topics from the perspective of a three-year-old child.

The segment grew out of research into changing viewing habits and Sesame Street's declining ratings. Producers found that younger viewers responded strongly to Elmo, so they built a more sustained mini-show around him rather than the program's traditional magazine-style collection of short segments. Elmo explored subjects such as balls, dancing and pets through songs, animation, live action and puppetry.

Elmo's World premiered on November 16, 1998. Kevin Clash performed Elmo during the original run, while Bill Irwin played Mr. Noodle and Andrea Martin provided the voice of several characters. Production paused in 2009, and the segment was replaced by Elmo the Musical in 2012. A shorter, redesigned version returned in 2017.