Where do the Arclight Skins come from ?

So I love the Arclight theme for Vayne, Varus and Vel, but I was looking closely at the skins and I noticed that in the Splash Arts there are buildings. The architecture is not even close to anything we currently have anywhere else in runeterra, yet the architectural style remains the same in all 3 splash arts. Could it be Icathia ? If so what are Varus and Vayne doing there ? What other champs could use this skin line ? Could Riot be teasing a new place in Runeterra ?