What is the circle of fifths in music theory?
The circle of fifths is a tool used in music theory to show the relationship between the 12 pitches in Western music. It is represented as a circle, with each pitch arranged in a clockwise progression of ascending fifths.

Starting from the top of the circle with the key of C, each successive key is a fifth higher than the previous one, moving clockwise around the circle. So, starting with C, the next key is G, then D, A, E, B, F#, Db, Ab, Eb, Bb, and finally back to C.

In addition to showing the progression of keys, the circle of fifths can also be used to demonstrate the relationship between major and minor keys. Each major key on the circle is paired with its relative minor key, which is located three positions counter-clockwise.

The circle of fifths is a useful tool for understanding music theory and for composing and arranging music. It can help with key selection, chord progressions, and modulations.
What are some songs that use a circle of fifths chord progression?
Several songs use a chord progression based on the circle of fifths. Here are a few examples:

1. Autumn Leaves - This classic jazz standard composed by Joseph Kosma features a chord progression that follows the circle of fifths. The song is often played in the key of G minor or E minor, and its progression includes descending fifths.

2. Fly Me to the Moon - This song, made famous by Frank Sinatra and composed by Bart Howard, includes a circle of fifths progression in its chord structure. The progression contributes to the song's smooth and swinging feel.

3. I Will Always Love You - Dolly Parton's original version of this song contains a circle of fifths progression in the verse, which is also evident in Whitney Houston's cover of the song.

4. Pachelbel's Canon in D - Johann Pachelbel's famous piece, often played at weddings, contains a sequence of chords that follows the circle of fifths. This progression is repeated throughout the canon.

5. Let It Be - The Beatles' song, composed by Paul McCartney, includes a chord progression in the chorus that follows the circle of fifths.

6. Cruisin' - Smokey Robinson's song includes a chord progression that follows the circle of fifths. The progression contributes to the song's smooth and laid-back feel.

These are just a few examples of songs that use the circle of fifths in their chord progressions. The circle of fifths is a fundamental concept in music theory, and many composers and songwriters use it to create harmonically pleasing progressions.