Event

Avengers Disassembled
What Happened
The Scarlet Witch becomes mentally unhinged by the revelation that she at one time had a family of children with the android Vision - which were a product of her desires made manifest by her mutant ability to control magic.  Because she was born with the ability to control magic the Scarlet Witch lacked discipline and her uncontrolled desires resulted in dangers to her fellow Avengers.

Brought to a halt by Earth's Sorcerer Supreme Dr. Strange -  the menace of the Scarlet Witch's undisciplined use of magic was brought to a halt but not without casualties both mental and mortal to her friends and teammates resulting in the destruction of Avengers Mansion and the disbanding of the Avengers.
Notable Deaths, Destruction or Introduction

Death

Ant-Man II

Jack of Hearts

Destruction

Avengers Mansion
Creators

Writers

Brian Michael Bendis

Artists

David Finch
Pertinent Issues
Avengers #500-503 (Sept. - Dec. 2004)

Avengers Finale (Dec. 2004)

Captain America Vol. 4 #29-32 (Sept. - Dec. 2004)

Captain America & The Falcon #5-7 (Sept. - Nov. 2004)

Fantastic Four #517-519 (Oct. - Dec. 2004

Iron Man Vol. 2 #84-89 (Sept. - Dec. 2004)

Mighty Thor #582-587 (Aug. - Dec. 2004)

Spectacular Spider-Man Vol. 2 #15-20 (July - Dec. 2004)