Columbia subject headings:
Harvard subject headings:
Culebra Island (P.R.)--Colonization.
Land tenure--Puerto Rico--Culebra Island--History.
Public lands--Puerto Rico--Culebra Island--History.
Princeton subject headings:
Culebra (P.R.)--History.
Navy-yards and naval stations--Puerto Rico--Culebra--History.
United States--Defenses.