A condominium is a form of ownership where units of real property, such as offices or apartments, are individually owned, while parts of the property, used in common (such as hallways, elevators, or the grounds) are owned jointly by the unit owners.

In 1948 the Horizontal Property Act of Puerto Rico established a model for the law developed as the U.S. National Housing Act of 1961. South Florida developers were among the first to put it to use, following passage of the state’s Condominium Act of 1963.

During the early 1950s, Palm Beach’s cottages and villas had been replaced with low-rise apartments and cooperatives. After 1963 these buildings were also replaced, with high-rise, densely built condominiums.

Often “condos” were conversions from other forms of ownership, as in the case of 400 South Ocean Boulevard. A group of local businessmen hired Kennedy Center architect Edward Durrell Stone to design a six-story, 64-unit rental property with hotel amenities, known as the 400 Building. Plans to open for the 1963-64 season were ruined by the unstable economic climate following the Bay of Pigs and the Kennedy assassination. Rather than lose the 400 Building, the investors converted it into the first condominium in Palm Beach County. Units sold for less than $100,000; many are still owned by the families of their original buyers.

To save the 400 Building from possible condemnation, in 2000 the board initiated what turned into a $10 million renovation project, paid for by assessments on the unit owners. The original architect’s sons, architect Hicks Stone and landscape architect Edward Durrell Stone Jr., were enlisted for the design work.