Revolutionary weapons that are under development in the U.S., China, Russia and other countries will have the capacity to travel at more than 15 times the speed of sound, to strike before any sonic booms or other meaningful warnings reveal their presence, and to penetrate any surface with the force of three to four tons of TNT.

The rush to possess these weapons has created a new arms race that could upend deterrence norms and renew Cold War-era tensions.

Here’s what else is happening

Himalayas: Climate change has been “eating” glaciers on the mountain range much more rapidly in the last 15 years than in the previous 25, according to new study based on decades of satellite data. The shift is a threat to hundreds of millions of people, for whom the glaciers are a source of water and an insurance policy against drought.

Emissions reduction: Leaders from all 28 E.U. countries, which together represent nearly 10 percent of global emissions, are in Brussels to discuss a proposal that would get the bloc to net-zero emissions by 2050.

Britain: Conservative lawmakers narrowed the choice for the party’s next leader, who will become prime minister, to Boris Johnson, the bombastic longtime Brexit advocate, and Foreign Secretary Jeremy Hunt.

Slack: Shares of the workplace messaging company, whose platform has transformed office culture and communication, soared on the first day of trading to $38.50 a pop, up from its reference price of $26, bringing Slack’s valuation to $23 billion.