Halltorp is in an area rich in history and biodiversity, and most of the southern part of the island of Öland has been designated as a World Heritage Site.The limestone blocks obtained from the local alvar are exceptionally flat with little fashioning just as they come from the quarry and are very easy to stack for use in building construction.In 1991, a twenty five guest room addition was created in the form of a new wing sweeping to the west joining in L-Plan design to the older manor core.[3] The manor house was designed with an entrance facing east, such that upon entering the vestibule, a great hall lay immediately ahead where the present day dining room is situated.Many other rare and endangered species can be found to the east on the Stora Alvaret, although in this northern part of Öland the alvar habitat is more fragmented than in the south of the island where large expanses of limestone pavement ecosystem exist.