The immune system reboot

“I’m one of those wacky wild swimmers,” he says. “Rain or shine, summer or winter, regardless of what country I’m in, I try and find someplace.” To justify the appeal, he draws on nature writer Roger

A pride of lions silently patrolling the grassland at dusk; a cheetah closing in on its prey with mind-blowing speed; a watchful leopard curled artfully in a tree. There’s nothing quite like a big cat

Were the seeds of Civil War already written into the American Constitution?

The land Down Under seems ready-made for soul-stirring adventures. Its 16,000 miles of coastline are one long playground, with vertiginous cliffs riddled with hiking trails and reefs ripe for diving. There’s ancient flora and unique wildlife hiding in the rainforests, and cities that offer every activity under the sun. So pick up your hiking boots, paddle or flippers and get outdoors

From dark matter to deep-sea crabs, science still can’t fully explain these strange quirks of nature

When to use this chart 1 December at 00:00 UT 15 December at 23:00 UT 31 December at 22:00 UT On other dates, stars will be in slightly different positions because of Earth’s orbital motion. Stars tha