HARARE, Zimbabwe — When European nations in the 19th century wrested accountable governance from their monarchs by putting in place parliamentary systems, one area remained outside their scope. Foreign policy, it was said, was the “domain of the king.” That view is alive and well in today’s Zimbabwe. The Ministry of Foreign Affairs might as well close down. It is a mere cipher. President Robert Mugabe, 86, exercises sole power and despite the formation of a government of national unity (GNU) he brooks no interference from his purported partners.

JOHANNESBURG, South Africa — Entering the Rivers Church in Sandton, one of the richest neighborhoods in this city, feels more like entering a concert hall than a house of worship.

GOMA, Democratic Republic of the Congo — The streets are corrugated with black volcanic rock, while far above a pool of lava glows red in the night sky. The volcanoes in the eastern Congo, near the border with Rwanda, haven’t caused havoc to air travel like Iceland’s Eyjafjallajokull — in fact, most days in Goma are punctuated by the conversation-stopping roar of planes constantly ferrying aid in or minerals out — but they have killed hundreds of people in recent years and forced tens of thousands to flee.