Hi there, have been trying to build the "Onyx Throne" in one of my games, but found it completely unplaceable, and could only put it into my build queue after double clicking, in which it uses NO SPACE on the world map, and the picture for "Onyx Throne" is missing in the build bar.
Rushing the Onyx Throne does not make a building pop up anywhere on the map... Seems kind of bugged 

Image Link: http://img38.imageshack.us/img38/5725/screenshot4gp.png
Saw one other building with no picture on levelling my city to level 5.
Sincerely
~ Kongdej