 For many fishing villages, loot and contraband provided by pirates supported a strong and secretive underground economy in Cornwall.Legendary creatures that appear in Cornish folklore include buccas, knockers, Giants and piskies.Tales of these creatures are thought to have developed as supernatural explanations for the frequent and deadly cave-ins that occurred during 18th century Cornish tin mining, or else a creation of the oxygen-starved minds of exhausted miners who returned from the underground.