Though we can't prove the existence of one (or many) god(s), we can provide evidence for the power of religion. For good or for evil, faith factors into our everyday functioning: We've evolved to believe.
Spirituality means something different to everyone. For some, it's about participating in organized religion: going to a church, synagogue, mosque, and so on. For others, it's more personal—some people get in touch with their spiritual side through private prayer, yoga, meditation, quiet reflection, or even long walks.