These might be confusing questions and it is very complicated but here goes…
As you know many of the monuments and artwork of the ancient world have remained a msytery for a long time. To find out about these things archeaologists have pieced together details from artifacts and other items that they find.
For example the pyramids in Egypt…my assumption is that they had to do this because as time went on the pyramids had been forgotten.
Fast forward and faces are carved into the side of Mt Rushmore and someone placed into the mountain a time capsule like object to tell future civilizations why the mountain was carved out, who each of the people were and their signifigance.
With Mt Rushmore being kept up and millions of people visiting it every year is this “time capsule” inside really needed?
In other words I can’t see a time when any of our modern monuments will ever be forgotten enough that people will not know what they meant. I could see certain monuments not being kept up but it’s hard to imagine it being forgotten to the point where people would need to open up an ultra sealed “time capsule” to find out what it is and why it is there. I’m not just referring to MT Rushmore but also the White House and anything else around the world built in the last couple of centuries. What would need to happen over the course of the next 2 thousand years that certain monuments that are so important today are ancient mysteries tommorow?