GORGE CROSSER is a term used to describe a bridge that crosses a gorge. The two most common types of bridges used for this purpose are trestles and viaducts. A TRESTLE is a bridge composed of a number of short spans supported by a series of pillars, while a VIADUCT is a bridge composed of a number of arches or other structures that span a valley or other low-lying area. Both trestles and viaducts can be used to cross gorges, and both have seven letters in their names.