A more thorough explanation:

A penal colony is a place where convicts and political prisoners are detained, usually in a remote and isolated location within a country or its extraterritorial holdings.

Historical examples of penal colonies include:

• The Soviet Union's gulags in Siberia
• France's penal colony on Devil's Island off the coast of Guiana

These examples illustrate how penal colonies were often used as a means of punishment and isolation for those deemed a threat to the government or society. The harsh conditions and remote locations made escape difficult, and prisoners were often subjected to forced labor and other forms of mistreatment.