In 1948 José Manuel Áleman, who had fled Cuba in the wake of scandals surrounding his service as education minister under Ramón Grau San Martín, bought the Cape Florida property from the Deering estate.
His offer to donate the lighthouse and ten acres (four hectares) of land around it to the National Park Service was not accepted.

In 1950 the Dade County Planning Board announced a plan to build a highway connecting Key Biscayne with the Overseas Highway on Key Largo.
The project envisioned bridges connecting artificial islands, to be built on the Safety Valve and existing small keys to Elliott Key and on to Key Largo.
Áleman was expected to donate the right-of-way for a road running down the middle of the island to the first bridge at Cape Florida.
With the prospect of a major highway passing through his property, Áleman rushed to prepare it for development: he had it completely cleared, leveled and filled in.
A seawall was constructed along the western (Biscayne Bay) side of the Cape Florida property.

Áleman died in 1951, and the County soon backed down from its road and bridge plan.
His widow, Elena Santeiro Garcia, added to her Cape Florida property by buying an ocean-to-bay strip that had been part of the Matheson property.
It included a canal dug by William Matheson in the 1920s, extending from the bay across most of the island.
The land north of the canal was developed as part of the present-day Village of Key Biscayne.
Garcia sold the Cape Florida property in 1957 for US$9.5 million, but the buyer defaulted and died the next year.
Garcia sold the property again, for US$13 million.
Development started on a model community' of luxury homes and resort properties.
By 1962 the new developers were in financial trouble, and the property reverted again to Garcia in 1963.

Dade County began considering purchase of 50 acres (200,000 m²) around the Cape Florida lighthouse for a park in 1964.
Bill Baggs, editor of The Miami News,  campaigned for all the Cape Florida property to be preserved in a park.
U.S. Interior Secretary Stewart Udall inspected the property and recommended that it be preserved, although not with Federal funds.
In 1966 Baggs brokered a deal between Elena Santeiro Garcia and the state of Florida, in which Florida bought the property for US$8.5 million, of which US$2.3 million came from the U.S. government.
This land was named the Bill Baggs Cape Florida State Park, and opened January 1, 1967.
In 2004 a sign was installed to commemorate the site as part of the National Underground Railroad Network to Freedom Trail, for the Black Seminoles who escaped to the Bahamas.
In 1948 José Manuel Áleman, who had fled Cuba in the wake of scandals surrounding his service as education minister under Ramón Grau San Martín, bought the Cape Florida property from the Deering estate. His offer to donate the lighthouse and ten acres (four hectares) of land around it to the National Park Service was not accepted.
In 1950 the Dade County Planning Board announced a plan to build a highway connecting Key Biscayne with the Overseas Highway on Key Largo. The project envisioned bridges connecting artificial islands, to be built on the Safety Valve and existing small keys to Elliott Key and on to Key Largo. Áleman was expected to donate the right-of-way for a road running down the middle of the island to the first bridge at Cape Florida. With the prospect of a major highway passing through his property, Áleman rushed to prepare it for development: he had it completely cleared, leveled and filled in. A seawall was constructed along the western (Biscayne Bay) side of the Cape Florida property.
Áleman died in 1951, and the County soon backed down from its road and bridge plan. His widow, Elena Santeiro Garcia, added to her Cape Florida property by buying an ocean-to-bay strip that had been part of the Matheson property. It included a canal dug by William Matheson in the 1920s, extending from the bay across most of the island. The land north of the canal was developed as part of the present-day Village of Key Biscayne. Garcia sold the Cape Florida property in 1957 for US$9.5 million, but the buyer defaulted and died the next year. Garcia sold the property again, for US$13 million. Development started on a model community' of luxury homes and resort properties. By 1962 the new developers were in financial trouble, and the property reverted again to Garcia in 1963.
Dade County began considering purchase of 50 acres (200,000 m²) around the Cape Florida lighthouse for a park in 1964. Bill Baggs, editor of The Miami News,  campaigned for all the Cape Florida property to be preserved in a park. U.S. Interior Secretary Stewart Udall inspected the property and recommended that it be preserved, although not with Federal funds. In 1966 Baggs brokered a deal between Elena Santeiro Garcia and the state of Florida, in which Florida bought the property for US$8.5 million, of which US$2.3 million came from the U.S. government. This land was named the Bill Baggs Cape Florida State Park, and opened January 1, 1967. In 2004 a sign was installed to commemorate the site as part of the National Underground Railroad Network to Freedom Trail, for the Black Seminoles who escaped to the Bahamas.
Key Biscayne