waves; water waves; sound waves; gravitational waves; earthquakes; earthquake waves; electromagnetic waves; X-rays; society; fashion waves; waves of refugees; early warning; heat waves; wave properties; properties of waves; wave phenomena; Light; Reflection; refraction; focussing; focusing; Localisation; manipulation; metamaterials; Radio waves; Gamma radiation; interference; attenuation; Velocity; dispersion; polarisation; microwaves; Mechanical waves; surface waves; body waves; Energy; Frequency; wavelength; radiation; physics; interference; communication; wave particle duality; radar; geology; geophysics; tsunami; early warning system; ocean waves; radiation; rays; language; migration movements; Medicine; tomography