Listen to Kahan Wo Bachpan Key online. Kahan Wo Bachpan Key is a Bengali language song and is sung by Pankaj Kumar Mullick and Pahari Sanyal. Kahan Wo Bachpan Key, from the album Ankhite Raho Go Nandadulal, was released in the year 2020. The duration of the song is 3:03. Download Bengali songs online from JioSaavn.