We were out enjoying the sights on Independence Day. It was hot and sunny, a pleasant change from the wet weather, so we decided to visit a friend on Bainbridge Island. It's a short ferry ride but there's plenty of time to turn around an enjoy the skyline of Seattle. The ship had just gotten underway, we were out of the car and had wandered to the stern when we noticed a black cloud starting from a pier and rising fast. A fire had started. As we stood there, trying to figure out what was burning, where it was burning, and how serious it was, the sirens started. Then the Seattle fireboat raced past us, positioned itself, and started dousing the fire. It was all over in a few minutes.
We found out later it was an abandoned dock - quite empty, no permanent structures. I don't think they ever did find out what started it.