Wikipedia:Picture of the day/May 2013

The Varosha quarter of Veliko Tarnovo, a city in Bulgaria. Commonly known simply as Tarnovo, the city was capital of the Second Bulgarian Empire between the 12th and 14th centuries.

Photo: Plamen Agov

A diagram showing the chloralkali process, a major industry expected to be worth over $80 billion globally by 2017. At the anode (A), chloride (Cl-) is oxidized to chlorine. The ion-selective membrane (B) allows the counterion sodium (Na+) to freely flow across, but prevents anions such as hydroxide (OH-) and chloride from diffusing across. At the cathode (C), water is reduced to hydroxide and hydrogen gas. The net process is the electrolysis of an aqueous solution of NaCl into industrially useful products sodium hydroxide (NaOH) and chlorine gas.

Illustration: John C

The Asian Openbill (Anastomus oscitans) is a large stork found mostly in South and South-East Asia. They hunt in wetlands and prey on snails, water snakes, frogs, and insects.

Photo: JJ Harrison

Audrey Hepburn (1929–1993), in a promotional still for Love in the Afternoon (1957). Hepburn made her Hollywood debut with Roman Holiday in 1953, after shooting several films in Britain. She is one of only eleven people to win an Academy, Emmy, Grammy, and Tony Award.

Photo: Allied Artists

Pachira aquatica is a tropical wetland tree found in the swamps of Central and South America. The fruit, a nut, is edible and can measure up to 12 inches (300 mm) in length and 2.5 inches (64 mm) in diameter.

Photo: Lycaon

A panoramic view of Srinagar, the largest city of Jammu and Kashmir, India. Built on both the sides of the Jhelum River, Srinagar is home to over 1.2 million people. It serves as the state's summer capital.

Photo: KennyOMG

Several female black-faced impala drinking at a waterhole. Impalas are sexually dimorphic. Females can weigh 10 to 25 kilograms (22 to 55 lb) less than males and do not have horns.

Photo: Alchemist-hp

The St Kilda Town Hall in St Kilda, Victoria, Australia, was designed by William Pitt and built in 1890. Owing to a lack of funds, Pitt was unable to complete his design. The building is now a secondary office of the Port Phillip City Council.

John O'Neill

The Red-necked Stint (Calidris ruficollis) is a small migratory wader. It breeds in the tundra of Siberia and Alaska but winters in Southeast Asia and Oceania. The pictured specimen is in its winter plumage.

JJ Harrison

Kiril Lazarov (b. 10 May 1980) is a Macedonian handball player active since 1991. He currently plays for HBC Nantes and is also the captain of the North Macedonia men's national handball team.

Photo: Armin Kübelbeck

Plan 9 from Outer Space is a 1956 American science fiction thriller film written and directed by Ed Wood and following a crew of aliens intent on resurrecting Earth's dead as "ghouls". The film has been dubbed the "worst ever made": it features numerous continuity errors, visible crew and equipment, and footage of a recently deceased Bela Lugosi from earlier projects.

Poster: Tom Jung; Restoration: Otto Jula

Southern Lake in Parque del Este, a recreational park in Caracas, Venezuela. The park was designed by Roberto Burle Marx and opened in 1961. It has had various official names since then. In 2010, it was visited by an average of 270,000 people every month.

Photo: Paolo Costa Baldi

Lina Rafn (b. 1976) is a Danish singer, songwriter and producer active with the band Infernal. She had previously been a VJ on the show The Voice TV Danmark.

Photo: Jepsen

U.S. citizen Mark Satin (far left), director of the Toronto Anti-Draft Programme, counseling draft-age Americans at the Programme's offices in Toronto, August 1967. The Toronto Anti-Draft Programme was Canada's largest organization providing pre-emigration counseling and post-emigration services to American Vietnam War resisters.

Photo: Laura Jones

The Starry Night is an 1889 painting by the Dutch post-impressionist artist Vincent van Gogh. One of the artist's best known works, it was painted from memory and depicts the view outside van Gogh's sanitarium room window at Saint-Rémy-de-Provence, France. Van Gogh, however, was reportedly unhappy with it; he wrote that the "lines are warped as that of old wood".

Painting: Vincent van Gogh

The Treskilling Yellow is a rare 1855 postage stamp from Sweden. Meant to be in a blue-green colour, it was mistakenly printed orangish-yellow. In 1996 the stamp sold for $US 2.3 million at auction; it was sold again, for at least that sum, in 2010.

Design: P.A. Sparre

The Olds Motor Works (pictured between 1905 and 1920) was an automobile factory in Lansing, Michigan, US. Established by Ransom E. Olds of Olds Motor Works, it came under the ownership of General Motors in 1908. The plant was demolished in 2006–07.

Photo: Detroit Publishing Co.; Restoration: Jbarta

The Purple Swamphen (Porphyrio porphyrio) is a rail native to Eurasia and Africa. The species, thought to consist of numerous subspecies, prefers wet climates. They generally nest on a mass of floating debris or amongst matted reeds slightly above water level in swamps.

Photo: JJ Harrison

Rembrandt (1606–69) was a Dutch painter and etcher generally considered one of the greatest in European art history. The artist attained fame as a portrait painter, although he later painted numerous Bible scenes. In this 1659 self-portrait, known as Self-Portrait with Beret and Turned-Up Collar, he depicts himself in a way which shows "the stresses and strains of a life compounded of creative triumphs and personal and financial reverses".

Painting: Rembrandt

Machinery Hall, one of numerous buildings found in the Illinois Institute of Technology in Chicago. The Hall, built in 1901, was declared a Chicago Landmark in 2004.

Photo: Joe Ravi

A mosaic image taken by the Hubble Space Telescope of Messier 82, a starburst galaxy located about 12 million light years away, in the constellation Ursa Major. The galaxy is five times as bright as our own Milky Way.

Photo: NASA, ESA, and the Hubble Heritage Team

USS Arizona was a Pennsylvania-class battleship built for the United States in the mid-1910s. Before being modernized between 1929 and 1930, she spent most of her time in training exercises; this photograph dates from that period. Arizona was later sunk during the Japanese attack on Pearl Harbor on 7 December 1941, resulting in the deaths of 1,177 of the 1,512 crewmen on board.

Photo: Unknown; Restoration: Mmxx

Girls' Generation is a South Korean girl group formed by S.M. Entertainment in 2007. They found popularity beginning with their 2009 single "Gee", and in 2011 Forbes described them as Korea's most powerful entertainers. Left to right: Kim Tae-yeon, Kim Hyo-yeon, Seohyun, Choi Soo-young, Im Yoona, Jessica Jung, Tiffany, Sunny, Kwon Yuri.

Photo: LG Corp

Layout scheme of a Sukhoi Su-25 (details), a jet aircraft designed to provide close air support for the Soviet Ground Forces and used by various countries. Since production began in 1978, the Su-25 has seen combat in several conflicts, including the Soviet war in Afghanistan, the Iran–Iraq War, and the Russia–Georgia War.

Diagram: Altoing

The Mountain Bulbul (Ixos mcclellandii) is a songbird species in the bulbul family which ranges across the Indian Subcontinent and Southeast Asia.

Photo: JJ Harrison

The meeting place of the Australian Senate, the upper house of the bicameral Parliament of Australia, in Parliament House, Canberra. Established in the Australian Constitution, the 76-seat senate has 12 representatives from each of Australia's six states and two from each of the country's internal territories.

Photo: JJ Harrison

Saint-Jacques Tower is a monument in the 4th arrondissement of Paris, France. Measuring 52 metres (171 ft) in height, the Gothic tower is all that remains of a 16th-century church which was demolished shortly after the French Revolution.

Photo: Charles Soulier

Structure diagram of the human heart, an organ that provides a continuous blood circulation through the cardiac cycle, from an anterior view. Blue components indicate de-oxygenated blood pathways and red components indicate oxygenated pathways.

Diagram: ZooFari

A watercolor painter working in Dolceacqua, Liguria, Italy, using a round brush. Watercolor is a painting method in which paints are made of pigments suspended in a water-soluble vehicle. The traditional and most common support for watercolor paintings is paper.

Photograph: Dongio

Paul Simonon (b. 1955) is an English musician and artist best known as the bass guitarist for punk rock band The Clash. Since the band dissolved in 1986 Simonon has been a member of several acts. In 2011 he was working with Mick Jones to create a film based on the recording of The Clash's album London Calling.

Photo: Rama

The Deutsche Bank Twin Towers is a twin tower skyscraper complex in Frankfurt, Germany, which serves as the headquarters of Deutsche Bank. Each rising to 155 metres (509 ft) in height, the towers began construction in 1979.

Photo: Jürgen Matern