By slowing down your shutter speed (1/15sec) you can get some very interesting motion into otherwise static images
While in Washington DC last week I was able to get out one morning with my tripod for some early morning photography as the city came to life. I am increasingly drawn to longish exposures. For at least the last year or more I have been shooting all my moving water images with ND filters to draw out the exposure time and interject movement into the images. I experimented quite a bit this morning in DC with the same idea. Lengthen the time of the exposure with the tripod there to hold the majority of the scene crisp and sharp, while a small element within moved and created a sense of activity that would otherwise be lacking. This is one of my favorited from the day.