The cultural heritage, in line with directives of sustainability's European principles, should be protected to preserve memory and cultures; in this way others people could enjoy it, for a long time. To explain exactly cultural heritage, we refer to the definition introduced with L. n.310/1964 by Franceschini commission: "Everything that is testimony, having value of civilization"; so a definition that extends conservation concept from punctual heritage to diffused one. However, even today, when we think about conservation of cultural heritage, we refer erroneously only to heritage that we could found in archaeological sites, historic cities or museums; while conservation of cultural heritage should be extended to whole cities or landscapes. Within this general framework, it's clear that conservation of cultural heritage, local and diffused, can't exist without the knowledge of sites that must be protected. For this reason, we propose to make an operative instrument for knowledge, protection, conservation and prevention. This instrument is the Risk Map, it will be an informative system of cultural heritage, just like a particular type of data base, that will support scientific and administrative decisions of government, local authorities or research areas, responsible for conservation. In this way, the Risk Map, just as an urban planning, could help to make a documentation of cultural heritage and a conservation planning.