GRAND STAIRCASE
ROYAL THRONE
ROYAL HALL
Only Lights are allowed.
In here, you are allowed to talk to King Siwon and his royal assistant, Yesung, regarding official matters. (i.e., requesting for a house/room, telling who your servant is [if a noble], telling that you're already a couple, and telling that if you're going on hiatus.)
Lights can tour the palace, chat, take pictures, but you cannot touch any of the things you could see here.
Introduction of new Lights also occur here.
Respect the king.