Frozen bubbles in Canadian lakes - Methane gas bubbles underneath Vermillion Lakes in Banff National Park, Alberta, Canada. Normally the bubbles would break the surface but in low temperatures they freeze.
Lines: The photo exemplifies lines through what appears to be a road leading the observer into the big city. The photo illustrates a nice employment of depth of field, which truly provides power to the lines leading to the busy city
Leading Lines: S-curves- This photograph displays s-curves because the road creates a distinctive line in the image and leads you through the entire photograph. The "s" shaped curve of the road/line also adds a more interesting dynamic to the image.