May 21

Events
 * 1877 - Associates of Alexander Graham Bell trial test a telephone in the Pennsylvania Railroad Company shops. The company then became the first to make a permanent installation.

Births

 * 1901 –, American band leader (d. 1986)
 * 1904 –, American pianist (d. 1943)
 * 1913 –, Greek pianist (d. 1976)
 * 1918 –, American singer and comedian (d. 1988)
 * 1928 –, American disc jockey (freeform radio) (d. 1975)
 * 1933 –, French trumpeter
 * 1939 –, Swiss musician
 * 1941 –, English musician
 * 1941 –, American singer (The Isley Brothers)
 * 1943 –, British guitarist (The Animals)
 * 1944 –, American singer
 * 1948 –, English musician
 * 1954 –, American musician
 * 1955 –, American drummer
 * 1963 –, Musician (My Bloody Valentine)
 * 1968 –, Filipino child actress and singer (d. 1985)
 * 1972 –, Brazilian musician (CSS)
 * 1972 –, American rapper (d. 1997)
 * 1974 –, American rapper (Mobb Deep)
 * 1975 –, Welsh guitarist
 * 1976 –, American rock musician
 * 1976 –, Canadian rapper
 * 1978 –, Canadian singer (Three Days Grace)
 * 1981 –, German singer
 * 1985 –, British rapper
 * 1985 –, Italian singer
 * 1986 –, Mexican-American singer
 * 1992 –, American singer and actress