For centuries tall towers have been used for communicating: first via flags, beacons and semaphore, and then later by radio waves. In the late 20th century came the rapid expansion of mobile phone technology, with the service providers keen to find lofty locations to mount masts. Most are a simple metal pylon, whilst others are disguised (with varying degrees of success) as trees. And some have found a home in a folly – ancient or modern.
When the great folly builders of the 17th and 18th centuries were erecting statement buildings on the high points of their estates, they can little have known how useful they would be to the Board of Ordnance. The ‘Principal Triangulation of Britain’ was a trigonometric survey, begun in the late 18th century, which by determining precise coordinates of significant landmarks would enable highly accurate mapping. The main landmarks used were church spires, but ‘other remarkable objects’ were picked, and in the first decade of the 19th century over 50 towers, temples, obelisks, summer houses and follies made it into this category.