We consider several systems modelling the motion of rigid bodies in a viscous fluid. We discuss the long time behavior of solutions in terms of the fluid properties (incompressible or compressible) and on the geometric setting (bounded or unbounded domains in one or three space dimensions. The focus is on the adiabatic piston problem in one space dimension (compressible case) and on the large time behavior of a solid moving in an unbounded three dimensional incompressible viscous fluid.