We humans are ruled by our senses, and some of those senses "stick" longer than others.

A few years ago, I was walking through the streets of Boston on a fine spring morning. People's windows were open, and there was a sense that the entire city was waking up.

From the upper stories of an anonymous brownstone, what I assume to be opera was playing. It was an aria, and the woman singing had lifted her voice out of a strength of emotion I could, at that time, barely guess at. I couldn't tell if she was singing from sorrow or joy, but her voice struck me to the heart. I was rooted to the spot, and my eyes quickly overflowed. I wasn't happy or sad, just so full of emotion I didn't have any other way to express it.

I never found out what that music was, who sang it, or any other identifying information. I don't know if I'll ever hear it again. Except, of course, in my dreams.