Propelled solely by the sun, the world’s largest solar yacht set off from Monaco last fall.

A month into their quest to be the first to circle the world in a sun-powered ship, the European crew of the Tûranor PlanetSolar drew the curiosity of some locals in the Atlantic Ocean. “We stayed next to four magnificent sperm whales for nearly 20 minutes,” says the ship’s master, Patrick Marchesseau. “They seemed completely at ease with the silent visitor.”

A recently restored stepped pond in Rajasthan, India, dates from the 1500s. Photograph by Richard Cox. 

Roman aqueducts get most of the attention, but other ancient civilizations had notable waterdelivery systems too. India, for example, is pocked with thousands of deep, elaborately constructed cisterns known as step wells and stepped ponds.

Built as far back as the seventh century, both structures were used to collect rain and groundwater. To access the water—whether to drink, bathe, or worship—villagers descended stairs to its level. The wells' differences are architectural: Step wells are linear, with partly covered pavilions and stairs that face the water; stepped ponds are square, with open tops and zigzagging, Escher-esque stairs (above).

When British colonizers arrived in the 1800s, the wells were deemed unsanitary and fell into disuse. Today many are in states of decay, but lately a handful have been restored. The Indian National Trust for Art and Cultural Heritage aims to protect more of them—and possibly revive them for water harvesting in the country's arid regions. Architectural historian Morna Livingston supports the effort. "They're again a source of pride," she explains, "rather than a dump."—Catherine B. Zuckerman

Photograph by Richard Cox. NGM Maps

There are many things I wanted to find out when I had the chance to test drive the Chevy Volt, GM’s new electric vehicle. How many miles per charge? What’s the carbon footprint? But mainly, what happens when I put the pedal to the metal? So, when one of my official Chevy escorts told me, “the Volt’s got the same engine torque as a Camaro,” I took full license to floor it. Driving some 230 miles up Interstate 95, on a road trip from Washington, D.C. to New York City, I pulled even with none other than a white Camaro, signaled the opposing driver with the raise of an eyebrow and a suggestive nod, and let the engine howl. Chewing up highway at 95 mile per hour, the Volt smoked that Camaro—and this is on the electric battery?

Ninety miles above the Arctic Circle, the Swedish municipality of Kiruna is in trouble. The town center, population 18,000, sits atop one of the world’s largest iron ore mines. After 110 years of mining and more than a billion tons of ore, huge cracks deform the bedrock, and Kiruna must either see the mine shut down or move out of harm’s way. What to do? Well, move, of course. Residents, many of whom depend on the mine for jobs, have decided to gradually relocate central houses, shops, and even a 98-year-old wooden church (below) to more stable ground several miles away. Some buildings will be transported brick by brick; many will be constructed anew. Among the fi rst to go: the 1899 house of Kiruna’s founder. Railroad tracks, roads, and electricity lines have already started to migrate. The iron mine, key to new Kiruna’s survival , will remain active—but at a safer distance. —Hannah Bloch

 
A vapor cone blooms around an F-22 Raptor as it races through humid air during a supersonic flyby. Photo: Ronald Dejarnett, U.S. Navy

The problem: how to break the sound barrier without rattling windows or nerves on the ground below. NASA’s Dryden Flight Research Center is learning how to lessen sonic booms. With barrier-busting airplanes, says Dryden aerospace engineer Edward Haering, “you get shock waves at each gradation in the vehicle’s shape.” It’s when individual shocks from the nose, wing, and tail come together that we hear the thunder down below. That makes a streamlined design a first goal for less jarring supersonic flight. An experimental narwhal-tusk-like “quiet spike” on the nose can help mellow an aircraft’s boom. Newer designs seek to shape shock waves from across the plane to keep them from coalescing into a megaboom. “We think we’re close to having the right tools to design it,” says Haering. “All we’ll need then is the will to build it.” Which could mean, finally, flying from New York City to Los Angeles in less than three hours, without waking up everybody in between. —Thomas Hayden  

Pumped in from the Pacific, the water in this Chilean pool is 16°F warmer than the ocean. Photo: Eliseo Fernandez, Reuters. NGM Maps

Salt water from a southern ocean surrounds you. White sand lines the floor and shore. Sailboats dot the surface as snorkelers swim by. Welcome to … the world’s largest pool. 

See the full illustration.

Imagine a school of fish weaving through a network of pipelines at the bottom of a bay. Only instead of live fish foraging for food, these are robots patrolling for damage and pollutant leaks. Robo-fish can fit in places divers and submarines can’t. The first robotic fish, built in the 1990s, were around four feet long, had thousands of parts, and cost thousands of dollars. The newest, designed by MIT researchers Kamal Youcef-Toumi and Pablo Valdivia y Alvarado, are five to eighteen inches long, have about ten parts, and cost just hundreds of dollars. These sleek robots are made of a seamless, synthetic compound engineered to be flexible in places where fish bend a lot—the tail—and rigid where they don’t—the midsection. A single motor sends a wave down the interior, and the motion of the material mimics the swimming motion of a real fish. Although the latest robotic fish are pretty close to making a splash, they are not yet swimming in lakes and oceans. It’ll be a few more years before you can tell the story about the robo-fish that got away. —Juli Berwald

Photo: Robotic fish, strung up in an MIT lab, have lasted for four years in tests conducted in tap water. 

Photograph by Tim Laman

The plump neck on mummy Meresamun (above) made scientists think she had a goiter. Then they examined her with a high-resolution computed tomography (CT) scan and learned the truth: Her mummifiers had inserted a bit of stuffing to enlarge the Theban priestess’ neck.

In desert villages in Chile, 250 families are glad to let the sun roast their goat meat. The UN Development Programme paid $110 for the wood to build each solar oven. Fuel is free; pollution is nil. Women can spend time with kids instead of gathering wood. Solar Cookers International estimates one to two million solar ovens are now in villages, refugee camps, and sunny cities.

Solution: Synchrotron imaging, an x-ray technique more powerful than CT scanning and more precise than grindstone cutting. Over three years, French paleontologists Malvina Lak, Paul Tafforeau, and colleagues have used a synchrotron to sift through 25 pounds of 100-million-year-old amber and find 1,000 fossils, including wasps, flies, and spiders. An x-ray beam penetrates the rock-like drippings and pinpoints the encased specimens, which the team builds up as computerized models and produces in 3-D plastic form.

It began with a book. Not a famous book or a best seller but a science textbook, on the shelf of a community library in Malawi—one of 300,000 volumes donated to locations across Africa through the American Institutes for Research. Using Energy, by Professor Mary Atwater of the University of Georgia, had a picture on its cover that captured a 14-year-old William Kamkwanba's imagination, inspiring him to feats of invention. It was the image of a windmill.

In 2002 Kamkwamba had gone to the library in a stubborn attempt to continue his education. A drought had cut his family's food supply so he couldn't afford the fees necessary to enroll in secondary school. He knew little English and couldn't read most of Using Energy. But being the kind of guy who takes apart broken radios and fixes them, he was able to learn a great deal from the illustrations. He was sure he could build his own windmill using scrap from junkyards—an old bicycle frame, PVC pipes for blades. And he did.

To the amazement of fellow residents in the little town of Wimbe, when Kamkwamba hooked his windmill to a dynamo of the sort used to run a bicycle light off a rider's pedaling, his invention generated electricity.

Soon, Kamkwamba built another windmill to pump water from underground. A newspaper noticed. Then a blogger (although Wimbe did not have Internet access, and Kamkwamba had yet to learn the meaning of the world "Google"). Kamkwanba was invited to a TED conference and then himself became the subject of a new book, The Boy Who Harnessed the Wind, written with journalist Bryan Mealer.

What is a kilogram? It’s 2.2 pounds, of course. Or is it? The kilo is the only basic international standard pegged to a physical object—a 120-year-old platinum-iridium cylinder kept in a vault outside Paris and known as Le Grand K. In recent years scientists noticed slight variations in the cylinder’s weight. They’ve gone into high gear to redefine the kilo as a universal constant based on nature instead of an object vulnerable to distortion.

Quick, what’s faster than a speeding bullet and isn’t named Superman? The answer is the Bloodhound SuperSonic Car, or soon will be. Now being built in England, the jet-and-rocket-powered ride is designed to go, go, go 1,050 miles an hour. If it succeeds, it’ll blast past the current land speed record of 763 miles an hour, set in 1997 by Andy Green in the jet-propelled Thrust SSC. 

Just as gas-powered autos depend on oil, the world’s future fleet of electric cars may well depend on an obscure element now mined in only a handful of places: lithium. Because it is the world’s lightest metal and good at holding a charge, lithium in batteries can deliver the energy electric cars need without weighing them down or requiring frequent recharging stops.

Of all Pisa’s leaning towers—yes, there are several—the famous one is the least likely to topple. That’s because an 11-year restoration effort, involving three years of painstaking soil removal, has successfully steadied the precariously poised campanile. Pisa’s soil is mostly compressible clay and sand, which gives way over time and causes big buildings to shift.

It illuminated the Titanic, discovered hydrothermal vents on the seafloor, even located a lost hydrogen bomb. Now Alvin is ready for a new adventure: a major makeover. After 45 years and 4,500 dives, America’s hardest working, deepest descending submersible is slated for its biggest overhaul since 1973. According to Anthony Tarantino of the Woods Hole Oceanographic Institution, which operates the Navy-owned vessel, the upgrades will occur in two phases over several years, as funding permits. Those changes (left) will let the nimble, small-truck-size sub, which transports a pilot and two scientists, do more things better—like dive four miles instead of 2.8, and survey 99 percent of the ocean bottom versus 63. So don’t think of it as a midlife crisis; consider it Alvin 2.0, retrofitted for 21st-century exploration. —Jeremy Berlin

Click illustration to enlarge.

Art: Don Foley. Photograph by Dan Fornari, Woods Hole Oceanographic Institution

More than a billion people in the developing world need glasses. But opticians aren’t exactly on every block in sub-Saharan Africa. In some places the ratio is one to one million residents. Pondering this problem, Oxford University physics professor Joshua Silver came up with a brilliantly simple solution: a pair of eyeglasses, currently costing about $19, that the wearer can adjust. Silicone oil is injected into a gap between two sheets of plastic until the lens provides sharp vision. The inventor’s field research shows the correction can be better than that of prefab glasses sold at a store.

For centuries sandbags have stopped floods. They can fill in a divot in a dike or stand tall on uneven terrain. But hundreds of volunteers are needed to fill the bags—sometimes funneling sand through an upside-down traffic cone—and to schlep them to build walls. Inventors are devising more efficient devices: plastic modules filled with sand by a front loader, rubber tubes pumped full of water to weigh them down. Don Ward tests these higher-tech options for the U.S. Army Corps of Engineers and says they work well. “I’m amazed we still use sandbags,” he adds.

Photographer Tyrone Turner photographed the March 2009 coverage on energy efficiency and produced a striking set of images using a thermal camera. I had a chance to ask him about the challenges of the assignment.

Alex Trebek is a do-it-yourself host. On a lunchtime break from his duties as chief interrogator for National Geographic’s National Geography Bee on May 20 and 21, he picked up a dictionary and got busy. He had his list of questions (and answers) in a binder. If he saw a name he wasn’t sure how to pronounce—like Jengish Chokusu, a mountain peak on the China-Kyrgyzstan border—he’d look it up and insert diacritical marks to guide his tongue (the accent goes on the middle syllable of Chokusu). A consummate multitasker, he agreed to be interviewed while juggling questions and place names and sipping a glass of wine. “I have to work, so I must be half-tanked,” he joked.

Have you learned a lot of geography from hosting the Geography Bee for 20 years?
I’ve learned some stuff. But I’m not likely to retain the information. Keep in mind I have another program I do based on information that takes up a lot of my available random access memory. [Hosting the Bee] has taught me that many of our young kids are very well informed about the world. But I get to see the crème de la crème.

How would you do in the Bee?
Not particularly well. Any of the kids could beat me.

Most Bee contestants are male – as they are on Jeopardy, right?
There are now more women on Jeopardy than men, though that’s not always been the case. I think we’re about 55/45 women to men. Maybe it augurs well for the Geography Bee.

You’re Canadian. If you had to write a question about Canada for the Geography Bee, what would it be?
Most people don’t realize that this Canadian city lies directly south of a major American city.

Is it … Windsor?
Yes, it is Windsor … and Detroit!

Will there ever be another Jeopardy contestant like Ken Jennings, who won $2.52 million on 74 consecutive shows?
How do you even begin to dream that there is the possibility of another Ken Jennings? There might be, but it took us, what, 20 years to get Ken, and it might well take 20 more years to come up with somebody who will achieve or surpass Ken’s mark. Unless we find some contestant on steroids.

Do you have any favorite place names you get a kick out of saying?
Some names just sound great. Samarkand. In Asia. You cannot say Samarkand without thinking of something exotic. Just the sound of the word: Samarkand.

Any favorite North American place names?
Piscataway, New Jersey. Pis-CAT-a-way. Not PIS-ca-tawee. You drive through New Jersey and you want to exercise your pronunciation skills, just try to correctly pronounce a lot of the Indian place names. Your normal approach to pronounciation is thrown a curve. What’s the one in Florida? Kis-SI-mmee. Looking at it you’d think Lake KISS-a-mee!

It’s impressive that Jeopardy has become such a part of the fabric of people’s lives.
I got a letter recently from someone who told me about his mother dying. She went into a coma. They knew she was on her last hours. And his sisters went in and spent time. And because she had always watched Jeopardy, they turned on the program. One of the clues came up. She opened her eyes, and gave the response. And died. Came out of a coma and said, you know, “What is Panama … whatever.” Boom. Gone. I thought it was an amazing story.

Are you always being recognized by fans who go, “Alex, I’ll take potpourri for $100?
A lady recognized me on the street here in D.C., and she said, “Pat Sajak!”

Think you can match the 11-year-old who won the 2008 National Geographic Bee? Test yourself with the five questions from the championship round, then watch video of the tense final minutes.

-Marc Silver