Here is the full list of all 10 Triple Town achievements.
Built your first mansion
Built your first castle
Built your first sky castle
Built your first floating Triple Castle ... the pinnacle of civilization!
Created your first treasure chest
Built your first two-tier mansion using four or more houses
Built your first mega-castle using four or more mansions
Built your first mega-sky-castle using four or more castles (yeah, yeah, we know you're good at this!)
Terminated six bears in a single blow.
Terminated a dozen (12) bears in a single blow.