Libertalia was a legendary free colony forged by pirates and the pirate Captain Misson, although some historians have expressed doubts over its existence outside of literature. (Wikipedia)
There is an annual Libertalia Festival in Madagascar's capital Antananarivo.
The Pirate Republic itself was most likely located at Ile Sainte-Marie where a pirate graveyard nowadays attracts visitors.
Some evidence about Libertalia can be found in Antananarivo's small and hard to find Pirate Museum (www.piratenmuseum.li/).
There is some general pirate information
and some specific info about Libertalia.