The Beatles
The Beatles (pictured: Paul McCartney and Ringo Starr) were known for great pop songs that often featured unconventional instruments. Reuters

What makes a song timeless? It could be the harmony, the subject matter or something intangible that defies explanation. Creating a song may seem easy enough -- add some drums, bass, guitars and vocal -- but some musicians go above and beyond to deliver a unique listening experience. Berklee College of Music experts applied their expertise to figure out what instruments were used in Rolling Stone's Top 100 Songs of All Time. The instruments employed most often shouldn't surprise you, but what about the timpani, mouth harp or sleigh bells?

Berklee created an infographic of the 58 instruments that were played in the 100 songs. The Beatles and the Beach Boys were sonic innovators, but they weren't the only artists using obscure instruments to add another element to their iconic songs. Led Zeppelin used the bongos for "Whole Lotta Love" and the recorder and Mellotron on "Stairway to Heaven." The Rolling Stones used the guiro on "Gimme Shelter" and the tambourine on "(I Can't Get No) Satisfaction."

The marimba, oboe, sitar, harpsichord, harmonium, cabasa, swarmandal, contrabassoon, Clavinet, soprano saxophone and accordion are just a few instruments heard in just one song on Rolling Stone's list. You might expect whistling to appear more than once, but only song featuring the sound -- Otis Redding's "(Sittin' On) The Dock of the Bay" -- made the top 100.

Berklee staffers used their expert ears and documents to create the infographic, which can be viewed below.