In 1782, Customs & Excise Officer and soon-to-be-mayor of St. Ives John Knill built a vainglorious mausoleum so the local townsfolk would remember him. Upon his death in London in 1811, his will instructed that every five years, on July 25, 10 young girls, two widows, a local minister, the mayor of St. Ives, a violinist, and a tax man should engage in dancing, singing, and music around his 50-foot-tall, sharp-sided, triangular granite pyramid. And so an unusual local ritual began. To cover the cost of each celebration, Knill left £25…