It’s been an extraordinarily tense week in international relations, as the political shockwave from North Korea’s nuclear test rattled the world’s governments and tested their alliances. As scientists used seismic technology and radiation-detecting planes to work out just what it was that Pyongyang exploded deep underground near the Chinese border, the US ramped up its tough talk and the Chinese leadership seemed content to let the flare-up play out. But while the political fallout seemed enormous, whether or not the test actually changes anything is another question.

Elsewhere, our experts looked at fashion fads in the “little ice age”, gang violence in Rio de Janeiro, and Nigeria’s trouble with water. And former Greek finance minister Yanis Varoufakis told us how Britain’s departure from the European Union can still yield a better, more progressive future for both sides – as long as the political will is there.