Lahore was the cultural capital of the Mughal empire under Akbar, Jahangir, and Shah Jahan, and remains one of the most architecturally important Islamic cities of South Asia. The Badshahi Mosque, completed in 1673 under Aurangzeb, is among the largest mosques of the Mughal era and faces the Lahore Fort across a vast public square; the smaller Wazir Khan Mosque of 1635 inside the Walled City is a celebrated jewel of Mughal tile-mosaic decoration. Lahore is also home to the Data Darbar shrine of Ali Hujwiri (Data Ganj Bakhsh), an eleventh-century Sufi whose Kashf al-Mahjub is the earliest surviving systematic Persian treatise on Sufism, and the tomb of the philosopher-poet Muhammad Iqbal beside the Badshahi Mosque. Today Lahore is one of the most populous cities of Pakistan, with a vibrant tradition of qawwali, urs festivals at its many shrines, and large public observances of Ramadan and the major Islamic holidays.