In the modern era, Kenyan buildings can be seen in the background of Shaka's diplomacy menu. Shaka is from what is now South Africa so Kenyan buildings are out of place.
In the modern era, the Polish Culture Palace can be seen in the background of Hiawatha's diplomacy menu. Hiawatha was from North America so a Polish building is out of place.
In the modern era, New York City can be seen in the window outside Alexander's office. Alexander was from Europe, not North America.