Walk like an egyptian achievement

[Richard1806]

Hi everyone. I have been trying to unlock this achievement on the ps4. I have build the pyramids on a desert tile and after I build a sphinx on a desert tile. Both the same time. But I just can't unlock for some reason. Any help would be much appreciated thanks

 

[jargonaut]

Weren't you supposed to build them on desert FLOODPLAINS?

 

[Victoria]

Walk like a noobian