Historical sacred natural sites are natural sites associated with sacrifice, worship, healing, prayer or other religious or ritual activities according to folkloric, archaeological, historical, ethnological or other data.
Hiis, usually translated into English as sacred grove, is mostly a specific place that is called “hiis”. It can be a tree, grove, forest, stone, spring or landscape. The word “hiis” in its various dialectic forms has been used to describe the place, its sacredness and/or nature spirits that are believed to dwell there. “Hiis” as a place name is more characteristic to North Estonia; South Estonian people call their sacred places rather just sacred (sacred tree, sacred stone etc).
Hiite Maja Foundation works on not only the sacred groves (hiis) but all kinds of natural sacred sites: trees, forests, stones, springs, rivers, lakes, landscapes, etc.
According to archival and historical data, at least 550 sacred groves and 2000 natural sacred sites of other types can be found in Estonia.