Beyond the answers - interesting background to this quiz

When a capital is not a capital

Dresden is often mistaken for a national capital because of its size and fame, but Germany's capital is Berlin. Dresden is the capital of the federal state of Saxony and is known for its baroque architecture and art collections. Dublin and Doha, by contrast, really are the capitals of Ireland and Qatar respectively, which is what makes the odd one out tricky.

Ouagadougou and the Sahel

Burkina Faso's capital, Ouagadougou, sits in the Sahel, the semi-arid belt that stretches across Africa just south of the Sahara. Chad lies in the same region, which is why it fits the Sahel question. The Sahel is defined by its rainfall pattern rather than by borders, so it touches many countries at once.

A short hop across the Atlantic

The great-circle distance between London and New York is roughly 5,500 to 6,000 kilometres, depending on the exact points measured. That is why a transatlantic flight takes around seven to eight hours eastbound and a little longer westbound, where aircraft often fight the jet stream.

Agatha Christie's nursery rhyme murders

Five Little Pigs is a Hercule Poirot novel by Agatha Christie, published in the 1940s. Its structure borrows from the nursery rhyme, with five suspects each recalling the same past events differently. Christie remains the best-selling novelist of all time, which is why her titles turn up so often in quizzes.