effect on the previous status of an area. It might already have been other types of park, such as a national park. If the geopark branding is removed, it is still those other types of park. No matter what the type, management, the exercise of authority over the area, is always national; the scientific organizations have no sovereignity; they are simply advisory and certifying agencies guided by decisions made at international conventions. National geoparks A "national geopark" is a post de facto designation by UNESCO of a "geographical area" or a transnational geographical area already known to be "of international, regional, and/or national importance" as a candidate geopark. It has not yet been certified as belonging to a regional or the global UNESCO geopark network. It has been "already inscribed" as a member of some other network; that is, "national geopark" is a sort of floating candidacy that can be attached to any other parkland of interest, after which attachment the parkland qualifies for the designation of geopark. The candidates so designated are termed a "national network for geoparks." If it exists in a member nation all geoparks of the regional network in that nation as well as the global network must also belong to it. Some of the networks from which UNESCO national geoparks might be chosen are World Heritage Sites, Agenda 21, Man and the Biosphere Programme. UNESCO also provides a list of recommended geosite types, such as "minerals and mineral resources," "fossils," etc. The national networks (one for each nation) are intended as the bottom level of the bottom-up system. They support national conservation, education, cultural development, research, as well as economic sustainability. There is some effort to control conflict of mandate; for example, Fossils are not allowed to be sold, which practice would favor sustainability, but work against conservation. For some geoparks, such as Sitia geopark (east Crete), the conflict between geotourist development and the conservation of archaeological sites is a severe one, reaching the law courts. As with the other levels of geopark, the parks are subject to review for recertification every four years. Transnational geoparks A transnational geopark crosses a national border to extend continuously in two member nations. The park must belong to two national geoparks, one in each nation, and one regional geopark. Both national geoparks collaborate to prepare a single application, which is submitted by both to the regional and global