Gargoyles were introduced into Gothic architecture around the beginning of the 13th century, and were used on the upper parts of buildings -- usually churches, cathedrals, and castles -- to channel water away from masonry walls and foundations. In medieval times, the grotesque shapes of gargoyles were used to demonstrate the concept of evil, perhaps urging people to attend church more frequently -- or else. Congregants also believed that gargoyles kept evil away from the church by scaring away wicked spirits. After the installation of drain pipes in the 16th century, gargoyles became merely ornamental. These purely ornamental creatures are known as "grotesques."
Gutter language, Gothic style: