“Rats are our shadow selves.”

A report from Antartica, where the ecosystem is changing so fast scientists have no idea what will come next.

At 18, Katie Stubblefield lost her face. At 21, she became the youngest person in the U.S. to undergo the still experimental procedure to get a new one.

We know more about sleep than we ever have and we’ve never been worse at it.

It’s a made-up label.

How animals see.

Not long ago the idea of repairing the brain’s wiring to fight addiction would have seemed far-fetched. But advances in neuroscience have upended conventional notions about addiction—what it is, what can trigger it, and why quitting is so tough.

“Those who were born in the U.S.S.R. and those born after its collapse do not share a common experience,” wrote Svetlana Alexievich, who won the Nobel Prize in literature in 2015. “It’s like they’re from different planets.”

Life in Mosul.

On a 650-mile trek, two adventurers faced danger and hardship—and saw how development could spoil an American icon.

The discovery of a new human ancestor, hidden in a hard-to-access cave.

The question for researchers isn’t “How smart are dolphins?” It’s “How are dolphins smart?”

It’s the “City of the Big Automobile,” raw and beautiful at once.

In the deep ocean, a swimming sea-worm called a “green bomber” can throw sacs of light when attacked.

Trying to make sense our current age of disbelief.

A baby’s brain needs love to develop.

On spear-wielding chimps who hunt for meat.

Visiting the site of the Chernobyl meltdown.

When animals infect us.

On America’s combat canines and their handlers.

The perilous attraction of owning exotic pets.

Inside the minds of two people, one with the world’s best memory and one with the world’s worst.

On the foreign workers of Dubai, who now make up 90 percent of the city’s population.

A cave in Russia, a long-lost tip of a pinkie bone, and the discovery of a new kind of human being.

A writer embarks on a seven-year trek from Africa to Tierra Del Fuego.