Gary Winnick, a former junk-bond salesman who in 1997 founded Global Crossing, a telecommunications company that laid fiber-optic cable underwater around the world to speed internet and phone traffic, but that imploded five years later under billions of dollars in debt, died on Nov. 4 at his estate in Los Angeles. He was 76.

For a time, Mr. Winnick was the wealthiest person in Los Angeles, according to the Los Angeles Business Journal. He spread his philanthropy to the United States Holocaust Museum in Washington and to the Simon Wiesenthal Center and Cedars-Sinai Medical Center, both in Los Angeles.

In 2000, he bought his 40,000-square-foot, 60-room estate, called Casa Encantada, for $94 million from David Murdock, a billionaire businessman. He subsequently spent millions more renovating it. Four years ago, he listed it for $225 million. Its current asking price, $250 million, is believed to be the highest for a home ever publicly listed in the United States.