Two Trachylepis maculilabris skinks mating. Skinks are lizards that generally have no pronounced neck and relatively small legs. Females may be egg-laying or give live birth, with many of the latter being ovoviviparous (hatching eggs internally and giving birth to live offspring).

Photo: Muhammad Mahdi Karim

In projective geometry, Desargues' theorem states that two triangles are in perspective axially if and only if they are in perspective centrally. Lines through the triangle sides meet in pairs at collinear points along the axis of perspectivity. Lines through corresponding pairs of vertices on the triangles meet at a point called the center of perspectivity.

Image: DynaBlast

Satellite image of thick smoke in Borneo from numerous fires, most of them likely started by the "slash-and-burn" technique of local deforestation for agriculture, though logging activities may have started the fires accidentally. The exceptionally heavy smoke is caused by the burning of the peat in the peat swamp forests of the area and it results in air pollution, disrupts air traffic, and significantly adds to greenhouse gas emissions.

Image: Jacques Descloitres, MODIS Land Rapid Response Team

Bangalore Town Hall is a neoclassical municipal building in Bangalore, India. It is sometimes known, after a former president of Bangalore, as the Sir K. P. Puttanna Chetty Town Hall. Built by Mirza Ismail in 1935, it underwent renovations in 1990 at a cost of ₹6.5 million (US$371,400 at the time).

Photo: Muhammad Mahdi Karim

The royal coat of arms of the Kingdom of Greece from the restoration of George II in 1936 to 1973, when the kingdom was replaced by the modern Greek state. The escutcheon depicts the arms of the House of Glücksburg, imposed on the white cross on a blue field of Greece, with two depictions of Hercules that act as heraldic supporters. Around the shield is the cross and ribbon of the Order of the Redeemer. The motto at the bottom reads: "Ἰσχύς μου ἡ ἀγάπη τοῦ λαοῦ" ("The people's love, my strength").

Image: Sodacan

Hildebrandt's Starling is a species of starling named for Johannes Hildebrandt, a German collector who was the first European to obtain specimens. It is found in Kenya and Tanzania, where it occupies open woodland and open thornbrush country between 500 and 2,200 m (1,600 and 7,200 ft). Male and female adults appear identical, both having bright iridescent blue plumage on the upper body and upper surfaces with an orange-buff to rufous breast and belly. The juveniles are quite different, with charcoal grey upperparts and chestnut brown lowerparts.

Photo: Noel Feans

The transit of Mercury across the face of the Sun that took place in November 2006. Mercury appears as a black speck in the Sun's lower center-right region; the black areas on the left and right edges are sunspots. The transit was first recorded by French astronomer Pierre Gassendi on November 7, 1631. Transits of Mercury take place in May or November, at intervals of 7, 13, or 33 years, with the next one scheduled to appear in May 2016.

Photo: Mila Zinkova

The Slender Ringtail (Austrolestes analis) is a species of damselfly native to south-western and south-eastern Australia. It is active through spring to autumn near lakes, slow-flowing rivers and nearby vegetation.

Photo: JJ Harrison

Red-billed Oxpeckers (Buphagus erythrorhynchus) feeding on ticks found on this impala (Aepyceros melampus), an example of mutualism, which is defined as the way two organisms biologically interact where each individual derives a fitness benefit (i.e., increased reproductive output). Here, the birds gain food while the impala becomes free of parasites.

Photo: Muhammad Mahdi Karim

Friedrich Schiller (1759–1805) was a German poet, philosopher, historian, and playwright. He and Johann Wolfgang von Goethe were influential in the period known as Weimar Classicism. Together, they helped lead to a renaissance of drama in Germany and the Weimar Theater, which they co-founded, became the country's leading theater. This lithograph portrait is captioned "Friedrich von Schiller", in recognition of his 1802 elevation to the nobility by the Duke of Weimar (as indicated by the addition of the nobiliary particle "von" to his name).

Image: Unknown; Restoration: Lise Broer

An aerial view of Waikoloa, an ahupuaʻa in the South Kohala District on the northwest portion of the island of Hawaiʻi, with the Hilton Waikoloa resort hotel in the foreground. The region is named after Kohala, the oldest of the island's five volcanoes.

Photo: George

An artist's rendition of an Allosaurus fragilis with its jaws open fully, based on the research of paleontologist Robert T. Bakker. Allosaurus were active predators of large animals, and probably had the ability to open their jaws extremely wide. Studies suggest that they attacked prey open-mouthed, slashing flesh with their teeth, and tearing it away without splintering bones. Allosaurus was a genus of theropod dinosaurs that lived in the upper Jurassic period.

Image: Steveoc 86

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An illustration of how two mathematical surfaces, the helicoid and the catenoid, may be transformed into one another. This transformation is a local isometry. The catenoid was the first minimal surface to be discovered, by Leonhard Euler in 1744. Jean Baptiste Meusnier discovered the helicoid in 1766, and its name derives from its similarity to a helix.

Image: Wickerprints

Fritillaria meleagris is a species of fritillary native to much of Europe. In many places, including France, Slovenia and Romania, it is an endangered species that is rarely found in the wild, but is common in gardens. The flower may be pure white, but usually has a chequered pattern in shades of purple, which gives the plant its scientific name, as "meleagris" means "guinea fowl".

Photo: Yerpo

A 16th-century chiaroscuro woodcut of the Tiburtine Sibyl meeting with Augustus. The mythic meeting between the Roman Emperor and the sibyl (prophetess) of Tibur (now Tivoli), of whom he inquired whether he should be worshiped as a god, was a favored motif of Christian artists. In this scene, she shows him a vision of the Christian heaven.

Artist: Antonio da Trento; Restoration: Adam Cuerden

The Northern Curly-tailed Lizard (Leiocephalus carinatus) is a lizard species from the family of curly-tailed lizards (Leiocephalidae). It is native to the Bahamas, the Cayman Islands and Cuba, but was released intentionally in Palm Beach, Florida, in the 1940s. An active, robust lizard, it is mostly terrestrial and will retreat into a burrow or cavity when frightened. It prefers sunny areas with loose rubble and rock.

Photo: Ianaré Sévi

The White-faced Heron (Egretta novaehollandiae) is a common species of heron found throughout most of Australasia. It is a relatively small bird, typically weighing 550 g (1.21 lb) and ranging 60–70 cm (24–28 in) in height. It can be found almost anywhere near shallow water, fresh or salt, including residential fish ponds. Adults are pale, slightly bluish-grey, with yellow legs and white facial markings.

Photo: Benjamint444

A lithographed portrait of King George V of Hanover, his wife Marie of Saxe-Altenburg and their children Crown Prince Ernest Augustus (right), Princess Frederica (centre), and Princess Marie (left). George succeeded his father Ernest Augustus I as King of Hanover on 18 November 1851. His 15-year reign came to an end in 1866 when Prussia forcibly annexed Hanover in response to Hanover's support for Austria during the Austro-Prussian War.

Artist: Julius Giere

A species of assassin bug (Gminatus australis shown) feeding on a beetle. Assassin bugs use their long rostrum to inject a lethal saliva that liquefies the insides of the prey, which are then sucked out. The most distinctive feature of the assassin bug family is that the tip of the rostrum fits into a groove in the prosternum, where it is rasped against ridges there to produce sound, a tactic often used to intimidate predators.

Photo: JJ Harrison

A ripe avocado fruit, with the cross-section of another. The fruit (botanically a large berry that contains a single seed) is commercially valuable, and is cultivated in tropical and Mediterranean climates throughout the world. Trees are partially self-pollinating and are often propagated through grafting to maintain a predictable quality and quantity of the fruit.

Photo: Muhammad Mahdi Karim

The village of Glenridding, at the southern end of Ullswater, in the Lake District of England. The village is popular with hillwalkers who can scale England's third highest mountain, Helvellyn, and many other challenging peaks from there.

Photo: David Iliff

Two bipyramids of cassiterite, the mineral form of tin dioxide. Cassiterite, a widespread minor constituent of igneous rocks, has been the chief tin ore throughout ancient history and remains the most important source of tin today. Its lustre and multiple crystal faces produce a desirable gemstone.

Photo: Alchemist-hp

A 360° panorama of the night sky above Paranal Observatory, located on Cerro Paranal in northern Chile. This view shows the Milky Way forming an arc, the moon on the horizon just rising, the zodiacal light above it, and on the right, the Small and Large Magellanic Clouds.

Photo: H. H. Heyer, ESO

Beachy Head is a chalk headland on the south coast of England, close to the town of Eastbourne in the county of East Sussex. The cliff there is the highest chalk sea cliff in Britain, rising to 162 m (530 ft) above sea level. The peak allows views of the south east coast from Dungeness to the east, to Selsey Bill in the west.

Photo: David Iliff

The Australian Raven (Corvus coronoides) is the largest of the three Australian species commonly known as ravens. Measuring 46–53 cm (18–21 in) in length with a 100 cm (39 in) wingspan and weighing around 650 grams (23 oz), the adult is an all-black bird with black feet and beak and a white iris. It is common throughout south-eastern Australia and southern Western Australia, but it is not found in the far north. It has adapted very well to human habitation in some cities and is a common bird in Melbourne, Sydney, and Rottnest Island.

Photo: JJ Harrison

The European Hedgehog (Erinaceus europaeus) is a hedgehog species native to western and northern Europe. Adults are 20–30 cm (7.9–11.8 in) in length, weighing from 600 to 1,200 g (21 to 42 oz), depending on the season, with males slightly larger than females. It is nocturnal, and if alarmed will roll itself into a ball, protecting itself against potential predators with its spines.

Photo: Hrald

A fissure vent in the Fimmvörðuháls region of southern Iceland, caused by the 2010 eruption of Eyjafjallajökull. The eruption opened the 0.5 km (0.31 mi) long fissure on March 20, 2010, and a second eruption a week later opened a second fissure, as well as two craters, which were named Móði and Magni, after the sons of Thor, the Norse god of thunder.

Photo: Henrik Thorburn

The African striped skink (Trachylepis striata) is a skink native to southern Africa. Individuals are brown or bronze-coloured with two yellowish stripes that run lengthwise on either side of the spine. Both sexes grow to a length of about 25 centimetres (10 in).

Photo: Muhammad Mahdi Karim

The Small White (Pieris rapae) is a butterfly species native to Europe, North Africa, and Asia. It has also been accidentally introduced to North America, Australia, and New Zealand, where it has become a pest on cultivated mustard family crops.

Photo: JJ Harrison

The sulphur tuft (Hypholoma fasciculare) is a common woodland mushroom. This saprophagic small-gill fungus grows prolifically in large clumps on stumps, dead roots or rotting trunks of broadleaved trees. It has a bitter taste and is poisonous; consuming it can cause vomiting, diarrhea and convulsions.

Photo: Jörg Hempel