Dianne Feinstein passed away at the age of 90.

Feinstein’s death leaves a vacant U.S. Senate seat, requiring Gov. Gavin Newsome to appoint a temporary successor.

Feinstein started her public service career as president of San Francisco’s Board of Supervisors in 1978. She was also appointed Mayor of San Francisco before winning a special election for her U.S. Senate seat.

During her decades-spanning career, she was a major gun-control advocate, helped create the AMBER alert network, and sponsored bills protecting millions of acres of California desert.

She declared earlier this year she would not seek reelection at the end of her term in 2024.