With a tripod and a digital camera, it's fairly simple to take long-exposure photographs (like the Tokyo shot above, from Japan Wallpapers). Car headlights and taillights are a reliable source of purty light streaks.
Now what do you reckon the photo below is of?
That there is a super-long, six-month exposure taken at the UK's Bristol's Clifton Suspension Bridge, taken by Justin Quinnell. The light streaks show the passage of the sun over a half-year's time. What most impressed us was that this photo was taken using a pinhole camera made from a soda can and strapped to a lamppost!