Condominium ownership, which was introduced in the U.S. in 1961 and has since been widely adopted, implies separate ownership of individual apartments or units in a multiunit building. The purchaser of a condominium becomes th owner of a particular unit and of a proportionate share in the common elements and facilities. The unit may be separately mortgaged; the owner pays taxes and a fixed monthly sum to maintain the common elements. In the sale of a unit, the seller executes and delivers to the buyer a deed conveying all right, title, and interest in and to the entire condominium as well as the particular unit.