What is your interpretation of Stairway to Heaven?

I was recently going old favorites of mine and I remember listening to Stairway to Heaven and always having a sad feeling about the song even though I never really understood the lyrics.

Well I looked over the lyrics and I have a few different interpretations about it now but I’m not sure how accurate they are. I feel I’m missing or misinterpreting something in the song.

So what do you think the song was really about and how did you arrive at your interpretation.
I would like to hear different views on lyrics.