Yes, it's a stage!

It might be a duelling stage like here:

but otherwise it's simply a theatre:

Or more correctly an Aphitheatre, that is it's a semi-circular, acoustically vibrant open space. The columns are not fake, they're solid brick, but the building only imitates an ancient building (this one is patterned on the antic theatre in Herculaneum), being in fact built in the modern era. The cracks in the columns are made on purpose, to have it look old and ancient. It's not a matter of being in ruins, only resembling ruins, lol.

So now is the other question. When was it built? I'm not asking the year, only the epoch.

To make it easier (although I think it's very easy and you all know the answer in fact), several helping questions:
- When people where imitating everything what's old or exotic (Ancient Cultures, Dark Ages, Chinese)?
- The scene and the seats are separated with water, the trees behind the scene are used as a part of decoration - the elements of nature are to seem natural, so it's a part of English garden, where everything was to seem to be natural while in fact was all created by men. So when the English gardens came into fashion?
- The buildings of the epoch are to be found everywhere in the Western Civilization, the US included. So what famous American building could be situated together with the Amphitheatre?

Now, I believe it's more hints than needed to guess the epoch!

Sylwia