Are there any natural or man made threats to the Pantheon in Rome?

Are the rocks on the beaches of martha's vineyard natural or man made?

• On gayhead beach there is the clay cliffs. It's apparent this beach is eroding badly. There are a ton of rocks near the cliffs covering the beach as far as the eye can see. The rocks are up much higher near the cliffs and are all large and round. It appears these rocks are not natural and man made to stop the beach from eroding. Do you know if the tons of medium sized rocks are natural or there to stop beach erosion which is clearly happening.

• Answer:

  Martha's Vineyard is left behind from our last glacial episode. The unsorted nature of the rocks, and their rounded nature, would then be due to them being indiscriminately picked up and beat up by a glaciar and then dumped as the glaciar retreated when the earth warmed. Of course, I haven't seen them so they might have been placed specifically where they are to prevent erosion, but the rocks from Martha's came from glaciars.