The term “immovable property” shall have the meaning which it has under the law of the Contracting State in which the property in question is situated. For the purposes of this Convention property accessory to immovable property, in particular buildings, livestock and equipment used in agriculture and forestry, rights to which the provisions of general law respecting landed property apply, in particular any options or similar right to acquire immovable property, usufruct of immovable property and rights to variable or fixed payments as consideration for the working of, or the right to work, mineral deposits, sources and other natural resources shall also be treated as immovable property; ships and aircraft shall not be regarded as immovable property.