>>12750729the answer is obviously yes. Finding good evidence will be difficult, and it may not be deemed of high enough value to do so. During a sufficient period of time, say 5,000 to 10,000 years it becomes very likely of catastrophic events that would wipe out intelligent, but relatively small civilizations. Rare but devastating events like massive volcanic eruptions, astroid/metorite impacts, massive landslide, floods, fires, can wipe out civilazation and destroy evidence. Also, as can be seen in China, an emperor can transform a dynamic, intelligent, exploration driven society into an inward, backward retarded civilization and destroy hundreds or thousands of years of progress, experience, and knowlwedge.e