Final answer:
Mecca is the city where people of different religious philosophies and values would celebrate, especially significant as the site of the hajj, one of the pillars of Islam.
Step-by-step explanation:
The city that people would come to celebrate different religious philosophies and values is Mecca. Mecca was an important holy site even before the rise of Islam, with its center being the Ka'aba, a shrine built around a piece of volcanic rock that was worshiped in various Arabic faiths, and it was a major pilgrimage site for the Arabs. After the emergence of Islam, Mecca gained even greater significance as it became the site of the hajj, which is one of the pillars of Islam and a pilgrimage that every Muslim is obligated to perform if they are able. This convergence of trade and religious significance made Mecca a unique melting pot where people of various backgrounds and beliefs would gather, making it central to the Arabian Peninsula's social and religious life.