What's A Folly?

What exactly is a folly?

A folly is a deliberate piece of architecture created to look like a ruin. This was very popular during the Romantic movement in the 1800's.

Here is Wimpole's Folly. Take a look at the way that it is made.The left obviously resembles crumbling ruins, while the tower looks almost new. There is the lighter concrete area that looks like crosses and I think is supposed to be faux arrow-slits.

Grotto Hill was created to to look like ruins.

Grecian follies were also very popular.

Follies were also made as temples. See any resemblance to places that are created today?