Michael Jackson, defined in equal parts as the world's greatest entertainer and perhaps its most enigmatic figure, died suddenly this Thursday.

The 50-year-old musical superstar, dubbed  the King of Pop, was preparing for what would be a series of 50 concerts starting July 13 at London's famed 02 arena. Toiling for hours with a team of dancers for a performance, he was given an extensive physical exam before doctors cleared him for this series of performances which would have hopefully restored his tarnished legacy to its proper place in pop.

Jackson died at UCLA Medical Center after being stricken at his rented home in the posh Los Angeles neighborhood of Holmby Hills. Paramedics tried to resuscitate him at his home for nearly three-quarters of an hour, then rushed him to the hospital where doctors continued to work on him.

"It is believed he suffered cardiac arrest in his home. However, the cause of his death is unknown until results of the autopsy are known," his brother Jermaine said.

Cardiac arrest is an abnormal heart rhythm that stops the heart from pumping blood to the body. It can occur after a heart attack or be caused by other heart problems.

Jackson's death brought a tragic end to a long, bizarre, decline from his musical heyday in the 1980s, when he was popular music's premier all-around performer who shattered the race barrier on MTV, dominated the charts and dazzled even more on stage.

*Source: Msnbc.com