Cavers descend into the 'Well of Hell,' new clues about humans' arrival in North America and other stories you missed

PBS NewsHour's "5 STORIES" serves up the most interesting stories from around the world that you may have missed.

On this week's episode:

Cavers descend to the bottom of Yemen's 'Well of Hell' for the first time

A natural, 100 foot-wide sinkhole in the desert of Yemen's Al-Mahra province has inspired numerous ominous tales over the years. Among them, that the pit is home to the gates of hell, that it can suck objects into its opening and that men will be beheaded upon entry.

The sinkhole is officially named the Well of Barhout, but it also has a more dubious moniker: the "Well of Hell." The 367-foot-deep cave is millions of years old and believed to never have been explored until members of the Oman Cave Exploration team descended into it on September 15.

Once inside they didn't find genies, evil spirits, the gates of hell or any other evidence of local superstitions about the well. Instead, they discovered colorful geologic patterns and spherical calcium deposits called cave pearls – formed slowly over the millennia by dripping water.

The spelunkers spent several hours in the pit, avoiding a sizable population of snakes while collecting samples of rocks, dead animals and water. They hope the artifacts will eventually reveal clues to the pit's geologic formation.

One in two children in the U.S.have detectable levels of lead in their blood

Lead is a toxic metal that can cause irreversible damage to children's developing brains, including learning disabilities and behavioral problems. In the 1970s, it was removed from gas and paint in an effort to rein in human exposure across the country.

But despite efforts to control lead, a new study published in JAMA Pediatrics found more than half of kids under the age of 6 in the US have detectable levels of lead in their blood.

Race and poverty play a role in rates of exposure. More than 56 percent of children from predominantly Black and Hispanic zip codes had detectable levels of lead in their blood compared to 49 percent from predominantly white zip codes. That correlates with people living in homes that — on average — are older and more likely to have lead in their paint and pipes.

While effects increase with exposure, the CDC says there is no safe level of lead. To keep you and those you love safe, experts recommend testing soil around your home for lead content, removing lead-based paint flakes and dust from living areas and asking your local water authority if your home has a lead service line and how it can be replaced.

Coral reefs ability to provide food, jobs and climate protection drops by half since 1950

More than a half billion people depend on coral reefs for food, income and protection. The fragile ecosystems provide jobs for local communities, opportunities for recreation and coastline barriers against storms and erosion.

So, what happens when human activities start to kill coral reefs?

A September 2021 study led by University of British Columbia researchers explored how climate change, overfishing and habitat destruction all degrade reefs and their ability to provide essential benefits to humans.

The researchers found the capacity of the reefs to provide benefits to the ecosystem has declined by half since the 1950s. That's the same rate at which global coverage of living corals themselves have declined.

At the same time, the amount of effort fishermen put into catching the same amount of fish has increased while the biodiversity associated with coral reefs has declined by nearly two-thirds. It's a bleak finding when considering coral reefs have one of the highest levels of biodiversity of any ecosystem on the planet.

'Drowning' statue sparks conversations on sustainability and climate change

Mexican artist Ruben Orozco is making the Spanish town of Bilbao look at a serious problem, straight in the eyes.

His sculpture of a realistic face of a young girl was installed in the town's river in the middle of the night last Thursday. Each day since, the 264-pound fiberglass figure appears to drown as tide waters rise.

The sculpture, which is titled Bihar or "tomorrow" in English, is part of a campaign to encourage conversation around sustainability and climate change.

'Bihar' is the second of Orozco's pop-up art installations in Bilbao. In 2018, the life-size sculpture of an older woman titled, "Invisible Soledad" or "invisible loneliness," popped up on a park bench and stirred conversation around the isolated lives of the elderly.

Newly-discovered fossil footprints show earlier humans arrival in North America

Footprint fossils recently discovered at White Sands National Park in New Mexico are the oldest ever discovered in North America. According to a study published in the journal Science last week, some of the prints were made 23,000 years ago, a time when Ice Age ice sheets were at their largest.

That's 7,000 years earlier than scientists thought humans arrived in America. The discovery upends the theory that humans did not migrate to this continent until ice sheets receded.

The landscape is a desert now. But when these prints were made, it was a lush wetland where prehistoric beasts like mammouths, giant sloths and dire wolves once roamed.

The researchers say most of the footprints left in the ancient mudflats were from kids and teenagers, possibly at play, revealing new insights about the society of early people.