The five pillars of Islam are the foundation of Muslim life and obligations: Shahadah (professing belief in one God), Salat (prayer performed five times a day), Zakat (charity for the less fortunate), Sawm (fasting during Ramadan), and Hajj (pilgrimage to Mecca for those able). When interacting in Saudi Arabia, one should be aware of conservative social customs like modest dress for women, avoiding public mixing of sexes, and following etiquette around gifts, invitations, and dining. Foreigners are advised to dress conservatively and avoid prohibited acts like alcohol consumption or public displays of affection.