Agoraphobia involves an intense fear of situations where escape may be difficult or help unavailable in the event of developing panic-like symptoms. It is characterized by avoidance of situations such as traveling alone, being in crowded or enclosed spaces, or away from the perceived "safety zone" of home. Agoraphobia is classified as an anxiety disorder that often develops after panic attacks, causing sufferers to fear having another attack if exposed to the situations where the initial attacks occurred. Risk factors include a family history of anxiety disorders and experiences of stressful or traumatic life events.