voluntary natural reserve(Area of national interest which is protected under the responsibility of its owner in order to safeguard wildlife, archeological and geological sites)
voluntary work(Unpaid activities done by citizens often organized in associations, to provide services to others, particularly to elderly and poor people, handicapped, etc.)
early warning system(Any series of procedures and devices designed to detect sudden or potential threats to persons, property or the environment at the first sign of danger; especially a system utilizing radar technology)