Loona or 이달의 소녀 in Korean is a K-pop group by BlockBerry Creative. 

Pre debut 

In 2016 BlockBerry announced a new girl group that will start the project "Girl of the month", That consistsed in reveal one member every month with a single album, and subunits albums. Having 23 songs before the group debut.

Debut

They finally debuted in August 2018 with their first album as a group, “++”