Let us define an object as something you could pick up, perhaps with a forklift and put in the van and bring somewhere. So, say, the Taj Mahal will not be an "object" our criteria.
1) What was the most valuable object in the world in the early 1700s?
2) What is the most valuable object in the world today?
By the way, I know the (likely) answer to number one, but not to number two.