Wikipedia:Picture of the day/October 2013

ASony Alpha 77, fitted with a 16-50mm f/2.8 SSM lens. Announced in August 2011, the Alpha 77 has received mixed to positive critical reviews.

Photo: SkywalkerPL

The 2010 G-20 Seoul summit was the fifth meeting of the G-20 heads of government to discuss the global financial system and the world economy. It was held in Seoul, South Korea.

Photo: Presidencia de la Nacion Argentina

Gaspar de Guzmán, Count-Duke of Olivares (1587–1645) was a Spanish royal favouriteofPhilip IV and minister. As prime minister from 1621 to 1643, he over-exerted Spain in foreign affairs and unsuccessfully attempted domestic reform. His policies of committing Spain to recapture the Dutch Republic led to his major involvement in the Thirty Years War. This portrait was completed in 1634, with its composition referring to Olivares' military leadership in the service of King Philip.

Painting: Diego Velázquez

Poeke Castle is a castle near Poeke, Belgium. Standing on 56 hectares of park, the castle is surrounded by water and is accessible through bridges at the front and rear of the building.

Photo: Marc Ryckaert

Liocarcinus depurator is a species of crab found in the North Sea, Atlantic Ocean, Mediterranean Sea and Black Sea. Described in 1758 by Carl Linnaeus, it can be distinguished from other crabs by the curved rows of white spots on the carapace.

Photo: Hans Hillewaert

The Great Crested Grebe (Podiceps cristatus) is the largest Old World member of the grebe family. The species is skilled at swimming, chasing fish underwater.

Photo: JJ Harrison

Stephen Wolfram (born 1959) is a British scientist and the chief designer of the Mathematica software application and the Wolfram Alpha answer engine. Wolfram showed a propensity for the sciences from a young age, writing a dictionary of physics at age 12 and publishing his first scientific article at age 15.

Photo: Stephen Faust

Cueva de los Verdes is a lava tube in the Haria municipality on the island of Lanzarote in the Canary Islands (Spain). Historically used by local residents for protection, some two kilometres (1.2 mi) of the cave have been used as a tourist attraction since the 1960s.

Photo: Luc Viatour

The Walt Disney Concert Hall is the fourth hall of the Los Angeles Music Center and houses the Los Angeles Philharmonic and Los Angeles Master Chorale, among others. It was designed by Frank Gehry, with acoustics designed by Yasuhisa Toyota. The Disney family contributed more than $100 million to the project. The Dorothy Chandler Pavilion is seen to the right. This photograph was taken from near the corner of Grand Ave and 2nd Street, Los Angeles, California.

Photo: John O'Neill

The emerald-eyed tree frog (Rana platanera) is a species of frog in the family Hylidae found in South America.

Photo: Paolo Costa Baldi

The Munich Botanical Garden is a botanical garden and arboretuminMunich, Germany. Established in 1914, today it cultivates about 14,000 species. Pictured here is the garden's main building.

Photo: Diego Delso

The Blue-and-yellow Macaw (Ara ararauna) is a large South American parrot with blue top parts and yellow underparts. These birds are quite intelligent and are popular in aviculture. This specimen was photographed in Jurong Bird Park.

Photo: Luc Viatour

Caenorhabditis elegans (full size) is a free-living, transparent nematode (roundworm) which measures about 1 millimetre (0.039 in) in length. Males, such as the one pictured here, comprise a small minority of the species—just 0.05 percent—and can be differentiated from hermaphrodites by the adult male's smaller size, single rather than double-armed gonad, vas deferens, and fan-like tail specialized for mating.

Diagram: K.D. Schroeder

The history of the South SideofPittsburgh, Pennsylvania, begins with a grant of land in 1763. Here the area located at the confluence of the Monongahela (foreground) and Allegheny (background) Rivers is depicted in 1871, with what was then known as Birmingham in the right foreground and Allegheny in the distance on the left. The following year four boroughs (South Pittsburgh, Birmingham, East Birmingham, and Ormsby) were annexed into the City of Pittsburgh, and are now known collectively as the South Side.

Lithograph: Otto Krebs, Pittsburgh, Pa.; Restoration: Adam Cuerden

Union Pacific 844 at Painted Rocks, Nevada, on a run from ElkotoSparks, on September 15, 2009. Built in 1944, it was the last steam locomotive delivered to Union Pacific and is the only steam locomotive never retired by a North American Class I railroad.

Photo: Drew Jacksich; edit: Bruce1ee

L'Oceanogràfic is a marine park situated in the east of the city of Valencia, Spain. Designed by Félix Candela, Alberto Domingo, and Carlos Lázaro, the park was opened in 2003 and is integrated into the City of Arts and Sciences. Here the entrance is pictured.

Photo: David Iliff

Liocarcinus navigator is a species of crab in the family Portunidae. Its range covers much of the north-east Atlantic Ocean.

Photo: Hans Hillewaert

A geological map of Yosemite National Park (full size), showing the Cathedral Peak Granodiorite, the largest unit in the Tuolumne Intrusive Suite, which in turn is the largest granitic suite in the park.      Cathedral Peak Granodiorite      Rest of the Tuolumne Intrusive Suite

Map: Grandiose, based on a map by the United States Geological Survey

The Australasian Grebe (Tachybaptus novaehollandiae) is one of the smallest members of the grebe family. Native to greater Australia, New Zealand and nearby Pacific islands, this grebe was first described in 1826.

Photo: JJ Harrison

Sandboarding is a boardsport similar to snowboarding, but competitions take place on sand dunes rather than snow-covered mountains. Here, a member of the US Navy sandboards down a dune in Jebel Ali, Dubai.

Photo: Steven J. Weber/US Navy

"England expects that every man will do his duty", here represented with Popham's "Telegraphic Signals of Marine Vocabulary", was a signal sent by Royal Navy Vice Admiral Horatio Nelson, 1st Viscount Nelson from his flagship HMS Victory as the Battle of Trafalgar was about to commence on 21 October 1805. The English victory over Napoleon's forces in the battle removed all possibility of a French invasion and conquest of Britain.

Drawing: Ipankonin

Mona Lisa (La Joconde) is a half-length portrait of a woman by Leonardo da Vinci which was probably completed between 1503 and 1506, with further refinement continuing until 1517. Though the painting is thought to be of Lisa del Giocondo, a lack of definitive evidence has long fueled alternative theories as to the sitter's identity, including that it may represent Leonardo's mother Caterina in a distant memory. It has been held in the LouvreinParis since 1797 and is acclaimed as "the best known, the most visited, the most written about, the most sung about, the most parodied work of art in the world."

Painting: Leonardo da Vinci

The pin tumbler lock is a lock mechanism that uses pins of varying lengths to prevent the lock from opening without the correct key.

1. Without a key in the lock, the driver pins (blue) are pushed downwards, preventing the plug (yellow) from rotating.
2. When an incorrect key is inserted into the lock, the key pins (red) and driver pins do not align with the shear line; therefore, it does not allow the plug to rotate.
3. When the correct key is inserted, the gaps between the key pins and driver pins align with the edge of the plug.
4. With the gaps between the pins aligned with the shear line, the plug can rotate freely.

Diagram: Wapcaplet and Pbroks13

A Thousand Li of Rivers and Mountains (千里江山) is the only extant work by 12th-century Chinese painter Wang Ximeng. Measuring 11.9 meters (39 ft) in length, it has been described as one of the greatest works of Chinese art.

Painting: Wang Ximeng

ABeautiful Firetail (Stagonopleura bella) male (top) and female. In this common Australian species of estrildid finch, nest-building and raising children is done collaboratively.

Photo: JJ Harrison

A Bangladeshi child infected with smallpox, 1973. In ordinary type smallpox the bumps are filled with a thick, opaque fluid and often have a depression or dimple in the center. This is a major distinguishing characteristic of smallpox. The last naturally occurring case of smallpox was diagnosed on 26 October 1977, and in 1979 the World Health Organization declared the disease eradicated.

Photo: Centers for Disease Control and Prevention

The George Washington Masonic National Memorial is a Masonic building and memorial located in Alexandria, Virginia. Dedicated to George Washington, the first President of the United States and a Mason, the memorial was completed in 1932. Designed by Harvey Wiley Corbett, it is 333 ft (101 m) tall.

Photo: Joe Ravi

Saint George Palace is an historic building in the city of Rennes, France. Built in 1670, it was used as an abbey residence, replacing a much older abbey building that stood on the same site. During the French Revolution the abbey was closed and the property was seized by the government. Since 1930 the building has been listed as a monument historique of France. It now houses the fire services for the city and other civil administrative offices.

Photo: Julie Anne Workman

George Juskalian (1914–2010) was an Armenian-American member of the United States Army who served for over three decades, fighting in World War II, the Korean War and the Vietnam War and was awarded multiple decorations, including two Silver Stars and the Legion of Merit. After retiring from the military, he spent eight years working at Washington D.C.'s Southeastern University.

Photo courtesy of: Juskalian family

A newborn lesser short-nosed fruit bat (Cynopterus brachyotis) clinging upon a human finger. A species of megabat within the family Pteropodidae, it is a small bat that lives in South and Southeast Asia. Adults weigh between 21 and 32 grams (0.74 and 1.13 oz).

Photo: Anton Croos

The Mummy is a 1932 horror film directed by Karl Freund for Universal Studios. The film, starring Boris Karloff as a revived ancient Egyptian priest who seeks the soul of his long-dead lover, was inspired by the opening of Tutankhamun's tomb in 1922 and the rumored curse of the pharaohs. It has been remade several times.

Poster: Karoly Grosz