As the burial site of Shia Islam's second most important figure, this Mosque is considered by all Shi'ites as the fourth holiest Islamic site. The Boston Globe reports "for the Muslim Shias, Najaf is the "fourth holiest city", behind Mecca and Medina in Saudi Arabia and Al-Aqsa Mosque in Palestine." It is estimated that only Karbala, Mecca and Medina receive more Muslim pilgrims. A hadith attributed to Ja'far as-Sādiq, the Sixth Imami Shī'ite Imām, mentions the site as one of "five definitive holy places that we respect very much".