Where are the most significant cities in historical islam?

Kaaba.
A sacred building in the city of Mecca that housed the tribal idols until the rise of Islam in 7th century, when it became the center of Islam's most sacred mosque. Zamzam Well.
A well located in the city of Mecca that, according to Islamic belief, is a miraculously generated source of water from God.

Ithink it’s c , good luck on whatever : )