"The sun is always just about to rise. Mercury rotates so that you can walk fast enough over its rocky surface to stay ahead of the dawn; and so many people do. Many have made this a way of life. ...
Mercury's ancient face is so battered and irregular that the planet's terminator, the zone of the breaking dawn, is a broad chiaroscuro of black and white - charcoal hollows pricked here and there by brilliant white points, which grow and grow until all the land is as bright as molten glass, and the long day begun."
- Kim Stanley Robinson, 2312.
So far an excellent "hard" SciFi read in that it's full of fascinating ideas resulting from realistic facts, like Terminator, a city that traverses Mercury on a series of elevated train tracks that expands as the heat of the sun hits them, propelling the city forward ahead of the sunrise.