Complex and well-defined nanostructures are promising for emerging properties with broad applications. Self-assembly processes driven by diverse interactions generate varied nanostructures by using versatile nanocrystals as building blocks, while oriented attachment growth allows individual nanocrystals to be integrated and fused into highly anisotropic structures. By a combination of self-assembly technique and oriented attachment growth, many advanced nanostructures can be made. Such approaches can be viewed as an architecture of the nanoscale counterparts in the microworld, named as nanoarchitectures.