Popsugar Celebrity The Royals Prince Charles Facts 70 Things You Never Knew About Prince Charles 8 November 2018 by Corinne Sullivan View On One Page Photo 8 of 10 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 8 546: Number of engagements attended in 2017, which includes 374 UK events and 172 events abroad, making him the busiest royal of the year. 800: Number of guests who attended Charles and Camilla's wedding reception at St. George's Hall in 2005. 845: Number of the Naval Air Squadron he joined on the HMS Hermes in 1974 after qualifying as a helicopter pilot. 1,375: Cost, in dollars, of a 33-year-old slice of wedding cake from his first wedding auctioned off in 2014. 2,500: Average cost, in pounds, of lithographs of his watercolour paintings from his Highgrove Shop. 2,500: Number of guests who attended Charles and Diana's wedding at St. Paul's Cathedral in 1981. 4,000: Number of kilowatt hours of electricity produced per year by the solar panels he installed in the roof of Clarence House, his London residence. Previous Next Start Slideshow The RoyalsThe British RoyalsCelebrity FactsKing Charles III