Of all things British, 2 things (as my Mother would say) slay me - follies and fascinators .
a costly ornamental building with no practical purpose, especially a tower or mock-Gothic ruin built in a large garden or park
Examples are those stone monuments that are scattered about at Downton Abbey - the one behind the house that resembles a Roman temple.
And, if you were paying attention, there is one that looks like a rotunda that they run past while on the hunt. Basically they are what the well-to-do construct when they just want to spend money.
Fascinaters are another "invention" of the English. For centuries English women wore a hat every time they left the house, except when attending a ball or a dinner. These evolved over the years from fairly simple hats such as: