 A particular form of ridge soaring is "condo soaring", where pilots soar a row of buildings that form an artificial "ridge".This form of soaring is particularly used in flat lands where there are no natural ridges, but there are plenty of man-made, building "ridges".When the sun warms the ground, it will warm some features more than others (such as rock faces or large buildings), and these set off thermals which rise through the air.