Here's why:
* Retrospective literally means "looking back" or "considering the past." It's often used to describe an exhibition, review, or analysis that focuses on past events.
Let's look at other words with the root "retro":
* Retroactive: Applying to a period before enactment (e.g., a law that's retroactive applies to actions that happened before it was passed). While related to the past, it doesn't necessarily involve "looking back" in the same way as retrospective.
* Retrograde: Moving backward or declining (e.g., retrograde motion). This implies movement away from the past, not towards it.
* Retrospect: The act of looking back or reviewing the past. While similar to retrospective, it's more focused on the act of looking back rather than the result of that looking back.
Therefore, retrospective is the word that best captures the idea of looking back at past events.