A preservation easement is a legal document that regulates the uses of, or changes to, a property. Once a landmark property is placed under preservation easement, the easement "runs with the land" in perpetuity. Present and future owners must abide by its terms. Each easement is tailored to the particular situation. A preservation easement can prohibit certain alterations to the facade or exterior of a building, to important interior features, to its overall setting (including certain outbuildings), or to all of the above. Usually, the easement donor and the recipient group work out the details together.