Around the world, more than 40 teams are working on a vaccine for Covid-19. How one doctor is approaching the most urgent quest of his life.

A profile of climate activist Greta Thunberg.

Artist Eric Bealer was living the remote, rugged good life in coastal Alaska with his wife, Pam, an MS sufferer, when they made a dramatic decision: to exit this world together, leaving behind precise instructions for whoever entered their cabin first.

An interview with Richard A. Epstein of the Hoover Institution.

On water scarcity in Mexico City.

An early profile of Carole Baskin, proprietor of Big Cat Rescue in Tampa.

The U.S. may end up with the worst COVID-19 outbreak in the industrialized world. This is how it’s going to play out.

Snow science against the avalanche.

The polar icecaps are melting. Is it OK to have a child? Australia is on fire. Is it OK to have a child? My house is flooded, my crops have failed, my community is fleeing. Is it OK to have a child? It is, in a sense, an impossible question.

Anatomy of an outbreak.

How Big Oil and Big Soda kept a global environmental calamity a secret for decades.

Despite decades of research, myth and fear still surround the animals.

The fossil-fuel companies expect to profit from climate change. I went to a private planning meeting and took notes.

Daniel Kish is entirely sightless. So how can he ride a bike on busy streets? Go hiking for days alone? By using a technique borrowed from bats.

Decades ago, two parents sued a drug company over their newborn’s deformity—and changed courtroom science forever.

The story of the loneliest whale in the world.

How climate change is altering food in Greenland.

As medical researchers scramble to find the source of a fatal lung disease and officials seek to ban the sale of vape pens, our correspondent set out to separate reality from hysteria.

Oil-and-gas wells produce nearly a trillion gallons of toxic waste a year. An investigation shows how it could be making workers sick and contaminating communities across America.

How the Ebola outbreak spread.

On the shared life of Tatiana and Krista Hogan:

The girls’ doctors believe it is entirely possible that the sensory input that one girl receives could somehow cross that bridge into the brain of the other. One girl drinks, another girl feels it.

A new genetic engineering technology could help eliminate malaria and stave off extinctions — if humanity decides to unleash it.

Does hurting make us human?

“I wanted to be prepared for the worst nature could throw at me. But the real threat turned out to be human.”

On the centuries-long search for the perfect hangover remedy.