Question:  What annual event occurs on a property co-founded by an American who was the best-selling recording artist of the 20th century?

Context:
Mariah Carey
Mariah Carey (born March 27, 1969 or 1970) is an American singer, songwriter, record producer, and actress.
 In 1990, she rose to fame with the release of "Vision of Love" from her eponymous debut album.
 The album produced four chart-topping singles in the US and began what would become a string of commercially successful albums which solidified the singer as Columbia Records' highest selling act.
 Carey and Boyz II Men spent a record sixteen weeks atop the "Billboard" Hot 100 in 1995–1996 with "One Sweet Day," which remains the longest-running number-one song in US chart history.
 Following a contentious divorce from Sony Music head Tommy Mottola, Carey adopted a new image and traversed towards hip hop with the release of "Butterfly" (1997).
 In 1998, she was honored as the world's best-selling recording artist of the 1990s at the World Music Awards and subsequently named the best-selling female artist of the millennium in 2000.
List of pre-World Series baseball champions
The World Series, the modern championship series of Major League Baseball, began in 1903, and was established as an annual event in 1905.
 Before the formation of the American Association (AA), there were no playoff rounds—all championships went to the team with the best record at the end of the season.
 In the initial season of the National League (NL) in 1876, there was controversy as to which team was the champion: the Chicago White Stockings, who had the best overall record (52–14), or the St. Louis Brown Stockings (45–19), who were the only team to have a winning record against every other franchise in the league.
 The teams agreed to play a five-game "Championship of the West" series, won by St. Louis, 4 games to 1.
 Beginning in 1884, the championship series between the National League and the American Association were promoted and referred to as the "World's Championship Series" (WCS), or "World's Series" for short; however, they are not officially recognized by Major League Baseball as part of World Series history.
 Though early publications, such as Ernest Lanigan's "Baseball Cyclopedia" and Turkin and Thompson's "Encyclopedia of Baseball", listed the 19th-century games on an equal basis with those of the 20th century, "Sporting News" publications about the World Series, which began in the 1920s, ignored the 19th-century games, as did most publications about the Series after 1960.
 Major League Baseball, in general, regards 19th-century events as a prologue to the modern era of baseball, which is defined by the emergence of the two present major leagues.
Billy Joel
William Martin Joel (born May 9, 1949) is an American singer-songwriter and pianist.
 He was born in the Bronx, New York, and raised on Long Island, New York, places which have a heavy influence on his songs.
 Since releasing his first hit song, "Piano Man", in 1973, Joel has become the sixth best-selling recording artist and the third best-selling solo artist in the United States.
 His compilation album "Greatest Hits Vol.
 1 & 2" is one of the best-selling albums in the US.
National Sorry Day
National Sorry Day is an annual event that has been held in Australia on 26 May, since 1998, to remember and commemorate the mistreatment of the country's indigenous population.
 During the 20th century, Australian governments' policies resulted in a "Stolen Generation" – described by John Torpey as "Aboriginal children separated, often forcibly, from their families in the interest of turning them into white Australians".
True Love (Fumiya Fujii song)
"True Love" (styled "TRUE LOVE") is a single by Japanese recording artist Fumiya Fujii.
 It was released on November 10, 1993.
 It was number-one on the "Oricon" Weekly Singles Chart.
 It was the 29th best-selling single in Japan in 1993, with 806,000 copies sold, the 11th best-selling single in Japan in 1994, with 1.213 million copies sold and it is the 20th best-selling physical single in Japan, having sold a total of 2.023 million copies.
Mitch Miller
Mitchell William "Mitch" Miller (July 4, 1911 – July 31, 2010) was an American oboist, conductor, recording producer and recording industry executive.
 He was involved in almost all aspects of the industry, particularly as a conductor, and artist and repertoire (A&R) man.
 Miller was one of the most influential people in American popular music during the 1950s and early 1960s, both as the head of A&R at Columbia Records and as a best-selling recording artist with an NBC television series, "Sing Along with Mitch".
 A graduate of the Eastman School of Music of the University of Rochester in the early 1930s, Miller began his musical career as an accomplished player of the oboe and English horn, making numerous highly regarded classical and popular recordings, but he is best remembered as a choral conductor on television and as a recordings executive.
Bing Crosby
Harry Lillis "Bing" Crosby Jr. ( ; May 3, 1903 – October 14, 1977) was an American singer and actor.
 Crosby's trademark warm bass-baritone voice made him the best-selling recording artist of the 20th century, having sold over one billion records, tapes, compact discs and digital downloads around the world.
Del Mar Fairgrounds
The Del Mar Fairgrounds is a 370 acre property that is the site of the annual San Diego County Fair (called the Del Mar Fair from 1984 to 2001).
 Its Del Mar racetrack was built by the Thoroughbred Club in 1937 by founding members Bing Crosby and Pat O'Brien with Paramount Studios as corporate sponsor.
Glenn Miller
Alton Glenn Miller (March 1, 1904 – missing in action December 15, 1944) was an American big band musician, arranger, composer, and bandleader in the swing era.
 He was the best-selling recording artist from 1939 to 1943, leading one of the best known big bands. Miller's recordings include "In the Mood", "Moonlight Serenade", "Pennsylvania 6-5000", "Chattanooga Choo Choo", "A String of Pearls", "At Last", "(I've Got a Gal In) Kalamazoo", "American Patrol", "Tuxedo Junction", "Elmer's Tune", and "Little Brown Jug".
 In just four years Glenn Miller scored 23 number one hits - more than Elvis Presley (18 No. 1s, 38 top 10s) and The Beatles (20 No. 1s, 33 top 10s) had in their careers.
 While he was traveling to entertain U.S. troops in France during World War II, Miller's aircraft disappeared in bad weather over the English Channel.
Typewriter in the Sky
Typewriter in the Sky is a science fiction novel written by Scientology founder L. Ron Hubbard.
 The protagonist Mike de Wolf finds himself inside the story of his friend Horace Hackett's book.
 He must survive conflict on the high seas in the Caribbean during the 17th century, before eventually returning to his native New York City.
 Each time a significant event occurs to the protagonist in the story he hears the sounds of a typewriter in the sky.
 At the story's conclusion, de Wolf wonders if he is still a character in someone else's story.
 The work was first published in a two-part serial format in 1940 in "Unknown Fantasy Fiction".
 It was twice published as a combined book with Hubbard's work "Fear".
 In 1995 Bridge Publications re-released the work along with an audio edition.

Answer: San Diego County Fair