Why was mecca important as a religious center?

The Ka'aba was located there. The Ka'aba Was ancient religious shrine located in the ancient trading city Mecca. Before Islam there were many Arabs made pilgrimages there to worship their gods, they put statues of their gods inside the Ka'aba. Judaism and Christianity had spread through trade routes in Mecca. These Arabs believed there was only one god named Allah which means "almighty god" in Arabic. They believed the Ka'aba was a stone temple built by Abraham and Ishmael to honor Allah. One Arab named Muhammad came on the scene in the early 600s spoke out against all gods at the Ka'aba in Mecca. He said that Allah was the only true god and all other gods should be rejected. He added onto monotheistic Judaism and some Christian beliefs, that he believed he recieved from Allah, that would become the religion Islam which means "peace through submission to the will of god"

Because every muslim should go to La Mecca once in his life (Hajj)