Sometimes, what a head of state doesn’t say is as significant as what they do say. When French president Emmanuel Macron refused earlier this week to rule out sending Nato troops into Ukraine, he was potentially opening a new chapter in world history.

Nato currently only trains Ukrainian troops and provides them with weapons. It doesn’t engage in direct combat with Russia — and deciding to do so would amount to a rubicon crossed. Macron’s willingness to even open the discussion on changing gear poses two interesting questions: are Nato troops prepared for such a step and are the leaders of other Nato countries on the same page as Macron? Answers to those two questions here.

We don’t yet know what caused the devastating fire that destroyed two apartment blocks and killed at least ten people in Valencia last week, but, understandably, investigations are zoning in on the materials used to construct the buildings. “Innovative” cladding was a key factor in the unspeakable tragedy that unfolded in London in 2017 when Grenfell Tower was engulfed in flames. Even if the Valencia disaster doesn’t come down to cladding specifically, this eye-opening article is a wake-up call on how difficult it is for fire safety regulations to keep pace with all the new materials, processes and technologies emerging in the construction industry.

And in a world struggling with drought, we may soon need to rethink our general aversion to the idea of drinking recycled water. Researchers are already preparing for that time by finding out what makes a person more or less likely to be willing to gulp down what was once someone else’s shower. That way they might help convince us to take the plunge in the name of environmental responsibility.