1) Mountains are important water sources, as they capture and store precipitation, feeding rivers and supporting ecosystems downstream.

2) The first sound film, "The Jazz Singer," was released in 1927 and marked the transition from silent movies to "talkies."

3) Rihanna, born Robyn Rihanna Fenty, is a Barbadian singer, actress, and businesswoman. She has achieved great success in the music industry with hits like "Umbrella," "Diamonds," and "Work," and has also ventured into the worlds of fashion and cosmetics with her brands.

4) Elvis Presley, often referred to as the "King of Rock and Roll," has sold over one billion records worldwide.