Fortress Bridge

The Fortress Bridge is a massive stone viaduct that spans the River Helvander where it passes through Torrune, connecting the High City on the river's south bank to the Low City on the north bank. It actually consists of two separate spans, with the citadel of Beklagard at their mid-point in the center of the river; here the roadway of the bridge passes through a long, high-walled courtyard bisecting the upper levels of the fortress. This is, of course, the origin of the Fortress Bridge's name. Since the bridge, like Beklagard itself, was built with the aid of dwarven engineers and stonemasons in the Old Empire days, it is also often called the Dwarven Bridge. 
The south end of the Fortress Bridge meets the walls of the High City at the Griffin's Gate, and its north end terminates on the Low City waterfront at the Tower of Ghorodan just south of Talrik's Square. In the center, where the two spans reach the ramparts of Beklagard, massive drawbridges can be raised to separate the fortress itself from the end of either span. The Fortress Bridge is one of the three bridges that span the Helvander at Torrune; the others are Qorro's Bridge (or the New Bridge) a short distance upstream, and the Nyrrian Bridge connecting Fenside to the Low City another half-mile upriver from that. 
The bridge is an astonishing feat from an architectural perspective, far surpassing what human craftsmen are or were capable of. Its roadway is supported on a series of high, wide arches with surprisingly narrow piers at their feet, so that even the biggest river-barges can pass under it easily and the river's flow between the starlings does not become dangerously swift (as is often the case for Qorro's Bridge). The enormous, yet precisely shaped, stone blocks of its construction fit together so seamlessly that no mortar is needed between them. The Fortress Bridge has been standing for a thousand years, including decades-long periods in which Torrune itself was abandoned or fell into ruin around it, and it is hardly the worse for wear. To this day it has required very little upkeep or repair, and barring some unforeseen catastrophe, it could easily stand another thousand years.