Zundbridge

Located about 10 miles southeast from Waterdeep, where the Trade Way crosses the Dessarin River.

There is a Waterdeep guard post, a campground, and a water pump. Don't magically mess with the bridge, it's rumored to be a stone golem of some sort.

As for size, it's squat and massive. From the picture in Volo's Guide it looks about 15 to 25 feet wide.