At 275ft in height, Wainhouse Tower in Halifax is the world's tallest folly.
It was built as a consequence of an intriguing dispute between two Victorian landowners who vied with each other over the privacy of their estates.
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The tower was built between 1871-75 to serve as a chimney for John Wainhouse's dye works and, under the terms of the clean air laws of the time, could have been smaller, but Wainhouse was keen for it to be an imposing structure.
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However, in 1874 Wainhouse sold his mill, and the new owner refused to take on the expense of completing the tower's construction. Instead, Wainhouse kept it for himself for use as an observatory and viewing platform.
This had the added benefit of irritating rival landowner Sir Henry Edwards, who boasted of having the most private estate in the area. Once the tower was opened as a viewing platform, it overlooked Edwards's land.
The folly cost £14,000 to build and has 405 steps to the top. It is now Grade II-listed and open to the public only on Bank Holidays. Private tours can also be booked.
In 2006, safety problems led to the structure being closed, and a repair project began two years later. It re-opened in 2009 after a £400,000 restoration.