Now 40 years old, OPM was founded in 1986 by singer, actress and comedian Mitch Valdes and named by the late APO Hiking Society singer and composer Danny Javier. They call themselves the OPM Friends.

Hajji Alejandro, one of the country's OPM favorites, may have passed away, but his music will never be forgotten. Hajji had sung several OPM hits that turned into timeless classics in the Philippines.

Some songs naturally find their way into summer playlists—not because they mention the beach or vacations, but because they ...