Fall of Arcadia
From Tardis Wiki, the free Doctor Who reference
"I was there at the Fall of . Someday I might even come to terms with that."
-The Doctor
The Fall of Arcadia was a battle in the Last Great Time War. The Doctor was there, fighting on the front lines, and he witnessed the Fall. He later said that it would take him a long time to recover from it. (DW: Doomsday).