It can be thoracic or abdominal. Rupture can be catastrophic, unless promptly repaired. Repair of an unruptured on can be either surgical or endovascular with stent
graft. Symptoms depend on site of the aneurysm
and the structures compressed by it.
Thoracic Aortic Aneurysm:
Abdominal Aortic Aneurysm:
A good picture here: http://www.nlm.nih.gov/medlineplus/ency/imagepages/18072.htm