This city was gearing up to celebrate the 50th anniversary of what many view as the start of the modern civil rights movement (search). Those ceremonies must now go on without one of its greatest heroes.

Rosa Parks (search), whose Dec. 1, 1955, arrest for not giving up her seat to a white passenger sparked a bus boycott, died at her Detroit home Monday night of natural causes. She was 92.

"The only regret I have is that she didn't live to see the 50th celebration and to see how we are acknowledging her greatness," said Montgomery Mayor Bobby Bright (search). "It's a sad, sad day for Montgomery and a sad day for the world."

Bright was among the many admirers mourning Mrs. Park's death Monday. They cited her act of civil disobedience as triggering a 381-day bus boycott led by the Rev. Martin Luther King Jr.

The Rev. Joseph Lowery, who co-founded the Southern Christian Leadership Conference with the King and the Rev. Ralph D. Abernathy Jr., remembered Mrs. Parks Monday, calling her "the right person at the right time in history."

"Rosa Parks was known as the queen mother of the movement. She sat down so that her people could stand up," Lowery said Monday night from his home in Atlanta.

Tuskegee Mayor Johnny Ford said he would order flags in the town where Mrs. Parks was born as Rosa Louise McCauley on Feb. 4, 1913, to be flown at half-staff from Tuesday until after her funeral.

He said a street that was named after Mrs. Parks about ten years ago intersects with Martin Luther King Blvd., the roads symbolically coming together like their namesakes did so many years ago.

"The intersection of their lives lead to the bus boycott and the civil rights movement," Ford said Monday. "Rosa Parks was a gentle, yet a very strong woman whose resolve was unparalleled.

"She will be dearly missed by all of us."

There is a Rosa Parks Museum and Library at Troy State University at Montgomery and a brand-new Civil Rights Memorial Center in Montgomery was dedicated Sunday.

Commemorating events are planned all throughout 2006 and the celebrations are going to be bigger than previous years because it marks a half-century, said Bright, who says he keeps a picture of himself and Mrs. Parks in his office.

"She was such a peaceful person," Bright said. "There have been wars and great battles fought over much less and she never lifted a finger in hostility and yet to change the world with her actions ... her legacy of quiet and peaceful rebellion against hatred will live on for many years to come."