This is a paid asset, but now you can download gaea Free.
Detail this asset from Unity Store: Original Link
gaea v1.0
ENVISION KINGDOMS OF PEACE
This 3D asset kit combines natural materials and complex geometry with both Eastern and Western architectural influences. Fill your fantasy realms with beautiful cultural centers, banquet halls, intricate yurts, grand courts, and more – complete with artisan-crafted tables, decorative weavings, and earthenware vessels suitable for any learned kingdom or academic society.
This is a set of hand-crafted assets, built modularly so that you can customize any structure, with tileable textures that can be used with every model. This set comes with materials pre-built for any render engine, ready to use right out of the box.
Use this kit to create your own 3D world in game engines (Unreal, Unity) or traditional 3D software (Blender, Maya, 3ds Max, C4D, Houdini).