So Here's What I Learned:
Name: Atlantis
Sim Name: Atlantis (128,12

Theme: Underwater Sim, Atlantis.
Activities: Scuba Diving, Tringo, Ballroom (weddings), Submarine rides, Sightseeing
Unique: Underwater sim, beautiful coral reefs, excellent design.
Neualtenburg Improvements: To explore Atlantis one can rez a provided submarine, I was thinking Neualtenburg could have something similar to that, just more bavarian. Also a ballroom, will be a nice addition to Nburg.
Name: Rue D'Alliez
Sim Name: Rue D'Alliez
Theme: French
Activities: Shopping, Apartment Rentals, Ballroom.
Unique: Detailed buildings (not one is alike!), french theme, decorations by the roads, etc.
Neualtenburg Improvements: Market stalls, variety of buildings, more decorations.
Architecht: Versu Richelieu
- More decorations and scenery attract more resedential and commercial customers to Nburg.

(I'll find out more informations about other theme builds/sims later)