Spartakus and the Sun Beneath the Sea

Spartakus and the Sun Beneath the Sea is the English title of the French animated series Les Mondes Engloutis ( or "The Engulfed Worlds"), best known by American viewers as that trippy little series that ran on Nickelodeon for two years (1985-1987). You know, the one with the opening theme song sung by Menudo in Season 2.

The series concerns a lost city named Arkadia, whose ancient civilization escaped a great cataclysm by moving underground. Today, most Arkadians don't even know that life continues on the surface (thanks to the machinations of the ancients), and they would get on just fine under the light of their artificial sun Tehra (Shagma in the original French) - except that said sun is dying. Oh bugger...

With no other choice, a few Arkadian children defy the laws and enter the archive, using the knowledge about the surface they find there to create a messenger, Arkana, and send her for help. She makes it to the surface in Tehrig, and finds two ordinary human children, Matt (Bob in the original) and Rebecca, willing to go back with her. Unfortunately, Tehrig (Shagshag in the original) is captured by the Pirates of the Seas before reaching the portal back. They are eventually freed with the help of the wandering warrior Spartakus, but by then they are hopelessly lost, and have to wander the various worlds beneath the sea to find a way to Arkadia before it's too late.

This series contains examples of:

 * Apocalypse How: Arkadia escaped one cataclysm by moving underground. Now they're on the verge of another one.
 * Artificial Human: Arkana herself.
 * Atlantis: The Arkadians are hinted to be the last survivors from here.
 * Beneath the Earth: Arkadia and its inhabitants.
 * Cain and Abel: Spartakus has a younger brother named, I kid you not, Rainbow. However, there's no sunshine where he's involved, as he's the evil ruler of a kingdom and a slaver. And he wants nothing more than to see his older brother in chains.
 * Eternal French: The civilizations of the surface have been out of contact with the civilizations of the strata for millenia. So naturally, everyone understands each other just fine.
 * Expository Theme Tune
 * Gladiator Revolt - Spartakus (as might be guessed from his name) is an ex-gladiator who escaped slavery following a revolt.
 * Hollow World - the various "worlds of the strata" are just that . Entire worlds with skies, rivers , cities and people existing bellow the surface of the earth itself . What's more disturbing is that historical figures from our past actually live here as well (it is noted at the end of season one that time in the strata passes differently then on the surface).
 * Ineffectual Sympathetic Villains: The Pirates border on this trope.
 * Keep Circulating the Tapes: The French version has been released on DVD in Region 2. The English dub still hasn't been released anywhere.
 * Leitmotif
 * Lost Technology: None of the Arkadians know how all their whiz-bang stuff works anymore, beyond "push this button to make the machine do something useful."
 * Luke, I Am Your Father: Spartakus is an orphan and a major character. This was bound to happen.
 * Non Standard Character Design: The Pirates, who are much more toony-looking than the rest of the cast.
 * Orphan's Plot Trinket: Spartakus' trick gauntlet.
 * The Pirates Who Don't Do Anything: Semi-averted with The Pirates of the Seas. They will jump on you and loot your stuff... just as soon as they finish singing in their music video. The pirates also have a rival group of ruffians (who do not have their own song), lead by Ringnar , who also occasionally try to do something but fail.
 * Also much is made about Spartakus being the finest gladiator ever to roam the strata, but his combat skills are almost never used to solve a problem.
 * Really Seven Hundred Years Old: Bic and Bac, happy little critters resembling pangolins, who might be the oldest living things in Arkadia.
 * Shout-Out
 * Woman in White: Arkana.
 * Xtreme Kool Letterz: They're Greek. They can have all the K's they want in their names, dammit.