Eraklyon

Eraklyon is a planet within the Magic Dimension. It is Sky and Brandon's home world. Sky is the current king due to his father, King Erendor, who voluntarily left the throne and gave it to him. Sky's mother Queen Samara is still the current queen until Bloom and Sky are/get married.

Eraklyon was mentioned several times in the first season but wasn't seen until Sky and Brandon took Bloom and Flora to meet his parents in Season 2. During the visit, they learned that Diaspro was kidnapped and Sky immediately went to save her, raising Bloom's jealousy a bit.

In Season 3, Sky again invited Bloom and her friends to Eraklyon to celebrate Eraklyon's one thousandth year anniversary. Just before Sky was going to make an announcement, Diaspro put him under Valtor' spell.

And when Sky stepped forward to announce that he loved Diaspro, and called the Winx, witches, he broke Bloom's heart (literally). Later, the Winx girls find Valtor's mark on Sky's shoulder.

After the Winx escaped from Eraklyon (during which Stella earned her Enchantix) they went back to Alfea but went back some time later after Sky announced his engagement with Diaspro to remove Valtor's magic and break his spell. After they did, they fled before anything happened, during which Diaspro was found out and banished from Eraklyon. Some time later Sky returned to Bloom (after she earned her Enchantix on Pyros) to personally and heartily apologize for what had happened with Diaspro.

Trivia

 * In the comics, Eraklyon is spelled Heraklyon.
 * Eraklyon is derived from the Ancient Greek word "Herakleion", meaning "Of Herakles" (Herakles is the Greek Mythology version of the Roman hero Hercules), probably referring to Sky being the main hero of the series.
 * The Capital of Crete is also named Heraklion/Iraklion.
 * In Season 5, after Sky lost his memory, Princess Diaspro tells him that she comes from Eraklyon, though in the 4Kids dub, she hails from Isis. However, it is unlikely that the planet would have two seperate monarchies (Sky's family and her own). It is possible that she was pretending to come from Eraklyon to fool Sky in to talking to her, instead of Bloom.
 * Like all other worlds with ocean, Eraklyon could also contain an Ocean Gate which is guarded by an unknown Selkie.