International Cello Day is celebrated worldwide every December 29, honoring the legacy of Pablo Casals, a prominent Catalan cellist, composer, and conductor, regarded as one of the greatest cellists in history. The day marks Casals' birthday, who was born on December 29, 1876, and is credited with popularizing the cello as a solo instrument. Celebrations typically involve cellists organizing meet-ups, learning new pieces, or creating YouTube videos, while enthusiasts may choose to purchase new recordings or attend concerts. Casals became internationally renowned in the early 20th century, particularly for his recordings of the Bach Cello Suites, which contributed to his lasting influence on the instrument. International Cello Day serves as a tribute to his contributions to music and the cello community.