This would be a fun 3D model for the kids to make. 3D City by Anna Paschenko | Abduzeedo Design Inspiration
Flying fish City on Behance - id love to see more elaborate Monument Valley inspired structures!
Isometric Low Poly World by Kiril Climson, via Behance
4² Rooms on Behance
Russian Railways by Vladimir Andreev, via Behance
Isometric buildings: City Island Airport 2 on Behance
Informe Corporativo Metro de Medellín 2014 on Behance
Chart Worlds by mladen penev, via Behance