Mount Dhubab (also known as Mount Ra’yah) is where a famous miracle took place during the digging of the trench. The Prophet (peace and blessings of Allah be on him) struck a large rock which was reduced to pieces and emitted a light. Upon this the Prophet (peace and blessings of Allah be on him) gave the Muslims the glad tidings of the coming victories over Syria, Persia and Yemen.
(more to follow)
References: History of Madinah Munawwarah – Dr. Muhammad Ilyas Abdul Ghani, When the Moon Split – Shaikh Safiur-Rahman Mubarakpuri