  The phase transition in frustrated spin systems is a fascinated subject in
statistical physics. We show the result obtained by the Wang-Landau flat
histogram Monte Carlo simulation on the phase transition in the fully
frustrated simple cubic lattice with the Heisenberg spin model. The degeneracy
of the ground state of this system is infinite with two continuous parameters.
We find a clear first-order transition in contradiction with previous studies
which have shown a second-order transition with unusual critical properties.
The robustness of our calculations allows us to conclude this issue putting an
end to the 20-year long uncertainty.
