Any city of this state, however organized, bordering upon any navigable or nonnavigable stream, river, or body of water, including any international or interstate navigable or nonnavigable stream, river, or body of water, is authorized to acquire, purchase, construct, maintain, and operate bridges and approaches thereto across any such navigable or nonnavigable stream, river, or body of water, whether all or any portion of bridges and approaches be within or without the corporate limits of the city, and to exercise all such powers within its boundaries and in adjacent territory within this state, not in excess of two miles from the nearest boundary line thereof, and in any adjoining domestic or foreign state, after first having obtained authority, if any be necessary, from the United States.