The Biblical Tower of Babel is revealed to have been an ancient Atlantean weapon (although subsequent episodes will reveal it was actually a communications relay; it's weapons capabilities were a secondary feature).
Sodom and Gomorrah are also revealed to have actually existed. They were actually destroyed by the Tower of Babel.
Asshole Victim: The soldier Gargoyle shoots in front of Nadia is still a henchmen of Neo Atlantis and thus involved in enslavement and massacres.
Bad Boss: In order to demonstrate how brutal he is, Gargoyle shoots one of his own soldiers. Nadia soon relents after this.
Cultural Posturing: Gargoyle shows Nadia how culturally superior Atlantis was relative to humanity.
Forced to Watch: Nadia is forced to watch the demonstration of the Tower of Babel.
Gargoyle knew Nadia as an infant and remarks she's as hard-headed as her Father. How he knows Nadia's biological family (and what happened to them) will gradually be revealed.
Similarly, Gargoyle's speech to his donors reveals they have spent 12 years on the Babel project, which would've been not long after this time period when Nadia would've been an infant. It'll be eventually revealed this project was necessitated by Nemo sabotaging and destroying the Tartessos Tower of Babel. Given the hell and chaos it unleashed, it makes sense it would take Gargoyle some time to take stock and figure out how they were going to have to try and recreate it from scratch with 19th Century technology.
It's a relatively minor, subtle one, but the reveal that Sodom and Gomorrah actually existed and were destroyed by the Tower of Babel. If they were done in by Atlantean weaponry, then what about Lot's wife and her transformation into a pillar of salt? Was that simply an erroneous detail added later, or was it due to some kind of Atlantean weapon? We'll finally get an answer of sorts in the series finale.
The Slave Stars reveals ancient Atlantis had the technological know-how and engineering to launch artificial satellites into orbit (to say nothing of creating particle accelerators for the Tower of Babel). Even if Atlantis was an advanced bygone civilization, how is that even possible?
It's also stated the Slave Stars have been dormant for 12,000 years. So this gives a time frame for the fall of ancient Atlantis. This provides another hint that the Atlantis of Nadia was a far, far older civilization than usual depictions, which further hints at the Ancient Astronauts origin.
Nemo knows Gargoyle is trying to develop a new Tower of Babel. On the first watch, it seems like intel he and his crew have collected or deduced in the course of the Secret War. It's only during the re-watch that it's clear he knows, because this was the trump card Gargoyle sought to secure 13 years earlier during his coup in old Tartessos.
Have We Met Yet?: Nadia has no idea who Gargoyle is, but he had met her previously 13 years ago when she was still an infant.
Kill Sat: The ancient Atlantean Slave Stars are a variation. They're not actually orbital weapons platforms, but rather orbital relays for a surface-to-surface based energy weapon.
Noodle Incident: From their dialogue after being thrown into the Atlantean prison cells, this isn't the first time the Grandis Gang has ended up in a cell and had to stage a jailbreak. Given their line of work, it'd be more shocking if they hadn't ended up in the hoosegow at least once.
Oh, Crap!: Nemo's grim reaction upon realizing the Neo-Atlanteans has completed a new Tower of Babel.
Plot Hole: A minor one with the concept of the Slave Stars. If they've been in orbit since the fall of ancient Atlantis, then somebody on Earth would've noticed these artificial satellites in the night sky at some point in the last 12,000 years and taken note of it (or tried to get a glimpse with early telescopes).
Surprisingly Realistic Outcome: Neo-Atlantis may be a secret society, but even they need donors and cash to keep the lights on and to finance their fancy toys like the Tower.
