Materials of nanoscale dimensions arouse remarkable interest, motivated by the diverse utility for nanotechnology. However, the functionality of materials is suppressed and often destroyed due to their extremely small dimensions. Using a state-of-the-art approach based on quantum mechanics, I have demonstrated that the mechanical stress or strain applied to materials strongly enhances, recovers, and sometimes newly develops, the electric, ferroelectric, magnetic, and various properties at the nanoscale, ie, “Multi-Physics”, due to nonlinear behaviors of atoms and electrons. Engineering mechanical strains at the nanoscale therefore enables us to exploit and design novel functionalities and open up new avenues for promising paradigms and novel functional devices.