Mugen Tsukiyumi is an illusion jutsu that can be done sejak projecting the user’s eyes into the moon. With it, Madara will control all the people in earth sejak an illusion.
With it, Madara can make the world a peaceful one… a world without ill will… the world without strife… everything will be one with him and are united.
However, the peace the Uchiha Madara is dreaming about is not the true peace according to the Kazekage (Naruto Manga Chapter 467 page 18) because the true peace is not true the illusion jutsu but the peace that the real world should accomplish sejak themselves.