Prostration is the placement of the body in a reverentially or submissively prone position as a gesture. Typically prostration is distinguished from the lesser acts of bowing or kneeling by involving a part of the body above the knee touching the ground, especially the hands. Major world religions employ prostration as an act of submissiveness or worship to a supreme being or other worshiped entities (i.e. God or the gods), as in the sajdah of the Islamic prayer, salat, or to show reverence to persons or other elements of the religion. In various cultures and traditions, prostrations are similarly used to show respect to rulers, civil authorities and social elders or superiors, as in the Chinese kowtow or Ancient Persian proskynesis. The act has often traditionally been an important part of religious, civil and traditional rituals and ceremonies, and remains in use in many cultures.