 Geographical constraints can complicate or prohibit the construction of a complete ring road.For example, the Baltimore Beltway in Maryland crosses Baltimore Harbor on a high arch bridge, and much of the partially completed Stockholm Ring Road in Sweden runs through tunnels or over long bridges.However, some towns or cities on seacoasts or near rugged mountains cannot have a full ring road, such as Dublin's ring road; or, in the US, Interstate 287, mostly in New Jersey (bypassing New York City), or Interstate 495 around Boston, none of which completely circles these seaport cities.