Answer: Its main and real reason is not clear to us; but noticing some points makes Mecca a suitable place for the Reappearance:
1. Mecca and the Kaaba has been the Kiblah (praying direction) of Muslims and people, every day, notice that holy place many times and prostrate towards it.
2. The Kaaba and Mecca are holy places wherein honorable divine prophets from Adam (PBUH) to
Muhammad (PBUH) have been presented by the order of Allah and have shown their submission in
addition to performing pilgrimage.
3. Mecca is the birthplace of Prophet Muhammad (PBUH) and the place where he was appointed to prophecy. Maybe the Reappearance of Imam Mahdi (PBUH) in Mecca shows that his Reappearance is the continuation of the movement of all divine prophets and His successors and it is aligned the prophethood of Prophet Muhammad (PBUH) and he wants to conclude centuries of effort and diligence of prophets and perform the religion of Truth by perfect establishment of justice in the world through his Reappearance. 1
References:- The book of “Aftab mehr” (The sunshine of affection), Mahdavi questions and answers.[↩]