In theoretical physics, massive gravity is a theory of gravity that modifies general relativity by endowing the graviton with a nonzero mass. In the classical theory, this means that gravitational waves obey a massive wave equation and hence travel at speeds below the speed of light. Massive gravity has a long and winding history, dating back to the 1930s when Wolfgang Pauli and Markus Fierz first developed a theory of a massive spin-2 field propagating on a flat spacetime background. It was later realized in the 1970s that theories of a massive graviton suffered from dangerous pathologies, including a ghost mode and a discontinuity with general relativity in the limit where the graviton mass goes to zero. While solutions to these problems had existed for some time in three spacetime dimensions, they were not solved in four dimensions and higher until the work of Claudia de Rham, Gregory Gabadadze, and Andrew Tolley (dRGT model) in 2010. One of the very early massive gravity theories was constructed in 1965 by Ogievetsky and Polubarinov (OP). Despite the fact that the OP model coincides with the ghost-free massive gravity models rediscovered in dRGT, the OP model has been almost unknown among contemporary physicists who work on massive gravity, perhaps because the strategy followed in that model was quite different from what is generally adopted at present. Massive dual gravity to the OP model can be obtained by coupling the dual graviton field to the curl of its own energy-momentum tensor. Since the mixed symmetric field strength of dual gravity is comparable to the totally symmetric extrinsic curvature tensor of the Galileons theory, the effective Lagrangian of the dual model in 4-D can be obtained from the Faddeev–LeVerrier recursion, which is similar to that of Galileon theory up to the terms containing polynomials of the trace of the field strength. This is also manifested in the dual formulation of Galileon theory. The fact that general relativity is modified at large distances in massive gravity provides a possible explanation for the accelerated expansion of the Universe that does not require any dark energy. Massive gravity and its extensions, such as bimetric gravity, can yield cosmological solutions which do in fact display late-time acceleration in agreement with observations. Observations of gravitational waves have constrained the Compton wavelength of the graviton to be λg > , which can be interpreted as a bound on the graviton mass