I remember once walking across the border from Laredo to Nuevo Laredo and being really struck by the difference. It was like traveling from Earth to Mars. One side green, the other brown. One side with nicely paved roads, the other with roads buckled and rutted. One side with well-dressed, well-fed children the other side with hungry children in tattered clothes. And on and on. Yet, the people on both sides were Mexicans ethnically. It was just the vagaries of politics and war that caused the amazing difference. The memory remains vivid today, many years after the experience.
Laredo to Nuevo Laredo and being really struck by the difference
That sounds worse than what I experienced between East and West Berlin in '80.