Photo of the Day 15 November 2007

Horse on Waterfront, Thessaloníki, Greece, 2004

Photograph by Massimo Bassano

A carriage horse pauses by the waterfront in Thessaloníki, Greece. This northern port city plays second fiddle to glorious Athens, but some say it offers a more authentic Greek experience: milder temperatures, picturesque views of mountains and sea, hidden gardens, ancient ruins, and by some accounts, the country's most flavorful cuisine.

Photo of the Day 14 November 2007

Attwater's Prairie Chick, Texas, 2002

Photograph by Joel Sartore

A weeks-old Attwater's prairie-chicken perches in a delicate nest in Fossil Rim Wildlife Center in Glen Rose, Texas. A century ago, as many as a million Attwater's prairie-chickens roamed coastal grasslands here. Today fewer than 50 of these chickens are left in the wild, due to overhunting and habitat loss.

Photo of the Day 13 November 2007

Aerial View, Lisbon, Portugal, 2002

Photograph by Tino Soriano

The church of Santo Estêvão, at right, watches over clusters of red-roofed homes along the Lisbon shore. Built by seafarers where the Tagus River empties into the Atlantic, Lisbon was once Europe's wealthiest capital and a center of world exploration. In 1775, a horrific earthquake in the Portuguese capital led to centuries of decline.

Photo of the Day 12 November 2007

Spider Guarding Eggs, Maui, Hawaii, 2001

Photograph by Darlyne Murawski

Found only on the islands of Oahu, Molokai, Maui, and Hawaii, the happy face spider, such as this one guarding its eggs on a leaf in Maui, is known for the unique patterns that decorate its pale abdomen. Scientists believe Theridion grallatormay have developed its distinctive markings to discourage birds from eating it.

Photo of the Day 11 November 2007

Grazing Giraffe, South Africa, 1977

Photograph by James Blair

A giraffe samples foliage in South Africa's Mala Mala Game Reserve. Biologist and explorer Mike Fay calls Mala Mala the "Ferrari of game reserves" for its posh, safari-retro accommodations, lush grounds, top-notch management, and abundant wildlife, including lions, leopards, elephants, rhinos, wildebeests, impalas, and giraffes.

Photo of the Day 10 November 2007

Devil's Marbles, Australia, 2000

Photograph by Cary Wolinsky

Colossal orbs of rosy granite serve as props for visitors' snapshots in Australia's Northern Territory. Known as the Devils Marbles, these naturally rounded boulders formed over a billion years ago when cooling magma in the Earth's crust forced up mounds of sandstone-covered granite. Wind, water, chemical, and mechanical erosion shaped the granite into their distinctive shapes, revered by Aborigines as the eggs of the Rainbow Serpent.

Photo of the Day 9 November 2007

Gull Island, Kenai Peninsula, Alaska, 1998

Photograph by Michael Melford

Gull Island, off of Alaska's Kenai Peninsula, is a refuge for hundreds of seagulls. One of Alaska's most heavily trafficked areas, the Kenai Peninsula abounds with postcard views—snowcapped mountains, rivers that roil with spawning salmon, an abundant supply of moose, bears, eagles, and puffins, four active volcanoes, and a gigantic, otherworldly icescape, Harding Icefield.

Photo of the Day 8 November 2007

Pair of Huskie Pups, Herbert Island, Greenland, 2006

Photograph by David McLain

These young pups on Herbert Island, Greenland, will grow up to be powerful, thick-furred sled dogs conditioned to survive long periods of exertion in subzero temperatures. A hardy breed descended from canines that accompanied immigrants who traveled from Siberia to Greenland some 5,000 years ago, Greenland dogs pull sleds that weigh upwards of a thousand pounds (450 kilograms) in temperatures near minus 70 degrees Fahrenheit (minus 57 degrees Celsius).

Photo of the Day 7 November 2007

Surf on Beach, Canary Islands, 2006

Photograph by Justin Guariglia

Surf spreads a foamy swath over a black beach in Gomera in Spain's Canary Islands. Gomera's tortuous geography—desert lowlands twist upwards into a soaring cloud forest—initiated the evolution of silbo, an indigenous six-note whistling language that allows the island's residents to efficiently communicate over hill and vale.

Photo of the Day 6 November 2007

Midges in Cueva de Villa Luz, Mexico, 2001

Photograph by Stephen Alvarez

Millions of iridescent-winged midges like these throng the inky depths of Cueva de Villa Luz cave in southern Mexico. Hydrogen sulfide, which is poisonous to humans, permeates the cave's walls, streams, and air, sustaining a rich variety of bizarre organisms. Midges, bats, spiders, mites, amblypygids, and small, hemoglobin-rich fish thrive in the sulfur-saturated environment.

Photo of the Day 5 November 2007

Royal Ascot Racecourse, England, 2007

Photograph by Peter Essick

In high spirits, a well-dressed crowd at Ascot Racecourse near London celebrates a day of horse races with singing and patriotic flag-waving. Scientists study the behavior of animal swarms, such as schools of fish, to predict the way humans might behave in such densely packed groups.

Photo of the Day 4 November 2007

Smiling Couple, Blackpool, England, 1998

Photo: English hipster couple

Pressed and polished, a suited commuter seems to shield his eyes from an embracing couple below. Government jobs, nightclubs, golf courses, and beaches draw an eccentric mix of pierced hipsters and buttoned-up conservatives to the seaside town of Blackpool in England's Lancashire county. Blackpool emerged as a major tourist destination in the 20th century, though it still retains its retro charm.

Photo of the Day 3 November 2007

Crocodile, Cape York Peninsula, Australia, 1995

Photograph by Sam Abell

Seventeen feet (five meters) of brute reptilian force, a saltwater crocodile snaps at the camera in Shelburne Bay, Cape York Peninsula, Australia. Earth's largest living crocodilians, "salties," as they're affectionately known in Australia, are among the area's most dangerous predators. Without warning, they explode from the water with a thrash of their powerful tails and drag their victim—water buffalo, monkey, shark—under water.

Photo of the Day 2 November 2007

Trekking the Namib Desert, Namibia, 1998

Photograph by O. Louis Mazzatenta

Alone in a vast expanse of sand, a man treks across giant dunes in Namibia's Namib Desert. One of the driest places on Earth, the Namib necessitates resourceful adaptations. Snakes, spiders, beetles, and lizards can survive here only because fog delivers a wisp of vital moisture as it rolls in from the ocean most nights.

Photo of the Day 1 November 2007

Great White Shark, Gansbaai, South Africa

Photograph by David Doubilet

On the prowl in Gansbaai, South Africa, a great white shark flashes rows of teeth sharper than daggers. With its numbers declining around the world, scientists warn that this species, the most feared of all sharks, may be in danger.

Photo of the Day 31 October 2007

Girl with Pumpkin, Louisiana, 2004

Photograph by Ken Kochey

In New Orleans, a young girl in a Halloween dress struggles to lift a large pumpkin. The tradition of carving pumpkins during Halloween began in the United Kingdom, where for centuries people cut scary faces into potatoes, turnips, and even large beets to dissuade evil spirits from entering their homes. Early European immigrants to America made these so-called jack-o'-lanterns from pumpkins, which are indigenous to North America and make an ideal canvas for such carved art.

Photo of the Day 30 October 2007

Slug Caterpillar, Manu River, Peru, 2001

Photograph by George Grall

Brushlike suckers radiate from the body of a slug caterpillar resting on a leaf near Peru's Manu River. The stinging hairs, or suckers, of these brightly colored, fleshy caterpillars contain mildly venomous toxins used for defense purposes. However, simply touching a slug caterpillar triggers toxin transfer, which causes rashes, swelling, and in some cases, fever and nausea.

Photo of the Day 29 October 2007

Aerial View of African Elephants, Kenya, 1999

Photograph by George Steinmetz

A herd of elephants makes its way through swamp grass in Kenya's Amboseli National Park. Established as a national park in 1974, the 151-square-mile (392-square-kilometer) park at the foot of Mount Kilimanjaro in southwest Kenya is home to more than 450 animal species, including elephants, wildebeests, cranes, and egrets.

Photo of the Day 28 October 2007

Celtic Festival, Edinburgh, Scotland, 2003

Photograph by Jim Richardson

Red-painted, torch-wielding revelers parade and dance in Edinburgh, Scotland, during the raucous Beltane festival, an ancient Celtic rite that heralds the May 1 start of summer. The popularity of this festival is part of an ongoing push by modern Celts to uncover the lost cultures of their ancestors—music, sacred sites, languages, and art styles that date back more than 2,000 years, when Celtic tribes dominated most of Europe.

Photo of the Day 27 October 2007

Bats in Cueva de Villa Luz, Mexico, 2001

Photograph by Stephen Alvarez

Bats emerge from the inky depths of Cueva de Villa Luz in southern Mexico. Hydrogen sulfide, which is poisonous to humans, permeates the cave's walls, streams, and air, sustaining a rich variety of bizarre organisms. In addition to bats, spiders, mites, amblypygids, and small, hemoglobin-rich fish thrive in the sulfur-saturated environment.

Photo of the Day 26 October 2007

Yawning Tiger, India, 1997

Photograph by Michael Nichols

Tigers, like this female in India's Bandhavgarh National Park, spend hot days in a languorous laze, storing energy for nights of hunting. Over the last hundred years, hunting and forest destruction have reduced tiger populations from hundreds of thousands of animals to perhaps fewer than 2,500. Today Bandhavgarh claims to maintain the highest density of tigers in the country.

Photo of the Day 25 October 2007

Silhouette of Westminster Abbey, London, England, 2000

Photograph by Jodi Cobb

The spires of Westminster Abbey cut dramatic shapes into a blushing twilight sky. The famous London church began as a Benedictine monastery enlarged by King Edward in the 1040s. It was designated the "west minster" to distinguish it from St. Paul's Cathedral, the "east minster." For centuries, Westminster Abbey has hosted royal coronations and burials.

Photo of the Day 24 October 2007

Llama in Pickup Truck, Chile, 2003

Photograph by Joel Sartore

A nervous llama lies in the back of a pickup truck amid the moonscape of Chile's Atacama Desert. Atacama's barren high plateaus are home to the Aymara people, who raise llamas for their meat and wool.

Photo of the Day 23 October 2007

Caterpillar on Fern, Hawaii, 2003

Photograph by Darlyne A. Murawski

A carnivorous Eupithecia caterpillar prowls a fern leaf in Oahu, Hawaii, in search of prey. Such predatory caterpillars are rare and possess extraordinary adaptations, such as armor shields, seductive smells, or artful camouflage, to enhance their lethality.

Photo of the Day 22 October 2007

Giant Quiver Trees, South Africa, 1995

Photograph by Chris Johns

Giant quiver trees rise from a rocky hill on the boundary of South Africa's Richtersveld National Park. These towering aloe plants, which can reach 33 feet (10 meters) in height, have suffered from heavy overharvesting and habitat loss and are considered critically endangered, with only a handful of specimens remaining.