Joan Rivers passed away today at the age of 81. The comedy legend was taken to a New York City hospital last week after she lost consciousness at her doctor's office while undergoing a procedure on her vocal cords. She was then put in a medically induced coma. Earlier this week, it was announced she was on life support and moved to intensive care.

With more than five decades of showbiz behind her, Rivers made a lot of friends -- and, yes, enemies -- over the years.

From her early stand-up act to hosting her own late-night TV show (where she welcomed David Lee Roth and Elton John as her first guests) to her weekly 'Fashion Police' show on E! (which also stars Ozzy Osbourne's daughter, Kelly), Rivers was known by practically everybody in the entertainment industry.

After the announcement of her death broke online earlier today, tons of people started to pay their respects on Twitter, including several rockers. Here are a few of them: