Jump Between World Capitals: Closest Pair Across the Equator with Map

Start with the two capital cities that are closest together across the Equator (one needs to be above the Equator and the other below it). Then do the same for the remaining capitals. Keep going!
When you guess an answer, at the end of it you are shown the initial letter of the answer below it (the initials of the first pair are shown in heading row above it)

You are shown distance in km and 'rhombus' bearing going from the 'above' capital to the 'below' capital.
After you have finished finding pairs across the Equator (because there's no more capitals in the Southern Hemisphere), move to pairs across the Tropic of Cancer for the remaining ones (2nd block of the quiz). For the very last ones (3rd block), find pairs across 41.9° N latitude