The Singapore Land Authority (SLA) is the definitive land authority in the country of Singapore. SLA uses GIS at the forefront of their Smart Nation initiative. They have mapped their entire country in 3D, with the goal to create a VR/AR environment of the entire country. GIS is also crucial for this small country in learning how to maximize their underground space.
Learn more, here: http://www.esri.com/products/arcgis-capabilities/3d-gis