Folly

:Folly is also a synonym for foolishness; see stupidity. A folly is a silly error.

Examples include

• The Folly Tower at Pontypool, Wales
• "The Cage" at Lyme Park
• Belvedere Castle, Central Park, New York
• Lucy the Elephant, Margate City, New Jersey
• Peckforton Castle
• Severndroog Castle, Shooter's Hill, south-east London
• Rushton Triangular Lodge, Northamptonshire (16th century)
• Wentworth Woodhouse, several follies in the grounds
• Stowe School, several follies in the grounds
• The Ashton Memorial, Lancaster, England
• Broadway Tower, The Cotswolds, England
• Désert de Retz, folly garden in Chambourcy near Paris, France (18th century)
• Hawkstone Park, follies and gardens in Shropshire, England
• Williamson's tunnels, probably the largest underground folly in the world, Liverpool, England