Frank Jacobs of Strange Maps has an enlightening post looking at Macaronesia, the collection of North Atlantic islands off the European and African coasts that includes the Portuguese Azores and Madeira, the Spanish Canaries, and the independent and ex-Portuguese Cape Verde islands. I wrote about this 2005, there noting how despite its independence Cape Verde was moving as quickly as poissible towards the European Union and its Macaronesian peers. The very idea of the region, Jacobs argues, is still obscure.
In its most common definition, Macaronesia consists of four island groups, belonging to three different countries: the Azores, the Madeira Islands  (both Portuguese possessions), the Canary Islands (Spain), and the independent archipelago of Cape Verde.
The name refers to the Fortunate Islands, a.k.a. the Islands of the Blessed (makaron nesoi), situated by ancient Greek legend beyond the Pillars of Hercules, in the Atlantic Ocean. As is the case with Atlantis, the precise mix of fact and fiction is hard to untangle in the case of the Fortunate Islands.
Perhaps those Greek legends were based on actual knowledge of the Canaries or other nearby islands. But their location beyond the horizon of the Greek world provided them with mythical qualities: island paradises rich in fowl and flowers, last resting place of heroes. According to Pliny the Elder, the only drawbacks were the “putrefying bodies of monsters, which are constantly thrown up by the sea.”
In later centuries, the Greek legends of happy faraway lands beyond the sea were conflated with similar Celtic legends (Avalon, Tir na nOg), with Viking explorations of Vinland and even with the Antilles.