Technically speaking, the entire wedding celebration is meant to commemorate one thing, your ceremony. During the ceremony you say vows to your soon to be sweetie-for-life, and the "altar" of sorts is what you stand before to immortalize your love for one another. Here are a few unique altar ideas; I hope you get inspired to make your ceremony site something special!
First Row: Pinterest Second Row: Matthew Morgan Photography via Ruffled Third & Fourth Row: Pinterest