Stonehenge

Stonehenge is a powerful image.
Not only for the Romantism, but also for all romantics after. It's age, it's mass, it's secret...
It's hard for an outsider to say if it has been used, inspired or both. I would say both. I would say that modern druidic movement and all spinoffs and varieties from he end of 19th century to the post-New Age 21st century would not be so strong without this powerful, inspirational symbol... (Stonehenge would thus be not only inspiration for all the art pieces mentioned in the lectures, but also indirectly for the art schools inspired by aforementioned spiritual movements.)
As a symbol, Stonehenge can be read in different ways, it can bear different meanings: For a scholar of prehistory, for an inhabitant of Amesbury, for British patriot, for neo-pagan...
In a hyperbole, I would say that Britain without Stonehenge wouldn't be Britain, as the Egypt without the pyramids wouldn't be Egyp (even when both the modern British and Egyptians are quite distant from their builders and their mental worlds...)