Piezoelectric crystals can generate electrical charge under an applied mechanical force and change shape under an applied electrical field. They have many applications in electromechanical devices such as ultrasonic transducers for medical imaging, actuators, etc. The piezoelectricity of a crystal is measured by the amount of strain that a crystal exhibits under an applied electric field or the amount of charge that a crystal generates under a stress. It has been a long-standing challenge to simultaneously achieve high piezoelectricity and light transparency in a crystal since the highest performance piezoelectric crystals are ferroelectrics containing high-density light-scattering domain walls within their domain structures. This presentation will discuss our recent computation-guided, rather surprising, discovery of simultaneous near-perfect light transparency and ultrahigh piezoelectricity in Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) crystals by understanding the ferroelectric domain evolution mechanisms under alternative current (AC) electric field poling using phase-field simulations. The newly discovered transparent ferroelectric crystals are expected to open up a range of electro-optical-mechanically coupled devices from high-throughput photoacoustic imaging to transparent actuators for haptic applications.