What does it mean - the hills are alive with sound of music?

"The hills are alive with the sound of music" is a phrase from the 1965 musical film The Sound of Music, which is a reference to the feeling of joy and happiness that can come from the sound of music. It is often used to describe a beautiful and uplifting experience, such as the feeling of being surrounded by nature and hearing the sounds of the birds and animals. It can also be used more broadly to describe any moment of happiness and joy, such as the feeling of being in love or the feeling of being part of a community.