My son was younger when we lived abroad (ages 3-6), but I have to say... it was completely wasted on him. A young child may not care about historical significance. Travel won't be a rare or unusual experience for them.
I distinctly remember standing on a bridge over the River Thames, trying to point out the Houses of Parliament to my then four-year-old son, and he got really excited and shouted, "Look, Mama! Look! IT'S A BUS!" (Not even the double-decker buses. It was just a regular bus)
This Mother's Day, his teachers asked him to fill out a questionnaire. To the prompt, "What was an exciting trip you took with your Mom?" my son, former frequent visitor to internationally-renowned museums, medieval cathedrals, Jacobean mansions, historic universities, falconry demonstrations, etc., wrote "Mama took me to Silver Dollar City." (A theme park in Branson, Missouri).
Your mileage may vary, but be prepared that they may just remember standing in a lot of lines, being bored in a lot of museums, or forget large swaths of the experience altogether.
The other thing is I think he felt quite rootless. He still frequently asks me, "Can we stay forever in this house? Can we not move ever again?"