Until the 1990s, there were almost no Jews in Nigeria. Now thousands of Igbo are taking up the faith, building synagogues in southern Nigeria.

Countries have hoarded masks, and used them as chips in geopolitical games. Thieves have made off with them. One mask broker described it “the craziest market I’ve ever seen.” The global scramble for this vital item has exposed the harsh realities of international politics and the limits of the free market.

Around the world, more than 40 teams are working on a vaccine for Covid-19. We followed one doctor, living like a monk in a Cambridge college room, engaged in the most urgent quest of his life.

Narendra Modi’s BJP is remaking the nation into one where some people count as more Indian than others.

At its finest, quizzing an exercise in nimble thinking — the only forum where the entirety of your life can be marshalled as pure knowledge.