We review some physics phenomena that can be explored with high electromagnetic fields. Such high fields are accessible using modern high-power laser facilities with a peak power higher than petawatt. High fields can modify the vacuum so that the birefringence or a change of refractive index can come into play as it behaves as matter under high laser fields. Moreover, if the field is high enough the field can break the vacuum – an electron-positron pair is generated. Such a field not only allows searches for the nature of vacuum or quantum electrodynamical effects but we even can explore new physics or new particles that are yet to be discovered.
