There's no reason that the sunset should signal the end of your picture-taking day. The night is filled with interesting and colorful subjects from city skylines to lighted monuments to glittery neon signs. Light levels are lower at night, of course, but your digital camera can record anything you can see. If you're traveling light (i.e. no tripod), you can just crank up the ISO speed (this regulates your camera sensor's response to light) and keep on shooting. Of, if you're a bit more serious about your work, bring a tripod along and you can use longer exposures for creative effect. I shot the neon sign shown here in Las Vegas using an advanced-zoom camera on a tripod. For lots of interesting ideas on after-dark shooting, see my complete night photography tutorial.