Islam originated with Abraham and his sons Ishmael and Isaac. The five pillars of Islam are the core beliefs and include Shahadah (proclaiming God's oneness), Salat (praying five times daily towards Mecca), Zakat (charity), Sawm (fasting during Ramadan), and Hajj (pilgrimage to Mecca). The Quran is Islam's holy book and Hadith contain the words of Muhammad. Symbols include the minaret for calling prayers, the Kaaba housing the sacred black stone, and the crescent moon. Mosques are places of worship and the Grand Mosque in Mecca can hold millions for Hajj. Rituals include