The properties of giant resonances in nuclei, atoms, atomic clusters a
nd condensed media are discussed. We present a comparative analysis of
similarities and differences between collective excitations in these
physical objects. The main conclusion: the existence of the giant reso
nance phenomenon does not depend on the nature of the particles and th
e interparticle forces. The necessary conditions are: the particles mu
st be moving in a confining potential and the number of them should no
t be small.