The Freedom Monument is a memorial located in Riga, Latvia, which honors the soldiers killed during the Latvian War of Independence. Designed by Kārlis Zāle and unveiled in 1935, this 42-metre (138 ft) monument includes thirteen groups of statues and bas-reliefs depicting Latvian culture and history. At the top is a 19-metre (62 ft)-high travertine column bearing the copper figure of Liberty lifting three gilded stars. Following Soviet occupation of Latvia in 1940, the monument was considered for demolition but ultimately saved. It remains a focal point for public gatherings and official ceremonies.

Monument: Kārlis Zāle; photograph: Diego Delso

Ophelia is an oil painting on canvas completed by Sir John Everett Millais between 1851 and 1852. It depicts the character Ophelia, from Shakespeare's play Hamlet, singing before she drowns in a river in Denmark; this death scene is not seen onstage, but is instead described in a speech by Queen Gertrude. The painting was completed in two stages: first, the setting (drawn from the Hogsmill River in Surrey) then Ophelia (portrayed by Elizabeth Siddal). The painting is now owned by Tate Britain and valued at more than £30 million.

Painting: John Everett Millais

A female Anthocharis cardamines, a species of butterfly in the family Pieridae. Found through Europe and into Asia, this butterfly prefers damp grassy areas.

Photograph: Michael Apel

The check used for the Alaska Purchase, issued on August 1, 1868, and signed by US Secretary of State William H. Seward. For a total of $7.2 million, the United States government purchased Russian America from the Russian Empire (represented here by Russian Minister to the United States Eduard de Stoeckl). The lands involved became the modern state of Alaska in 1959.

Check: William H. Seward; scan: Our Documents initiative

The yellow-bellied marmot (Marmota flaviventris) is a ground squirrel in the marmot genus. Found in the western United States and southwestern Canada, including the Rocky Mountains and the Sierra Nevada, these marmots live in colonies of about ten to twenty individuals, typically located in open areas at least 6,500 feet (2,000 m) above sea level.

Photograph: David Iliff

Adrianne Wadewitz (1977–2014) in a video (full resolution) discussing the workings of Wikipedia, created as part of the 2012 fundraiser. Wadewitz, an American feminist scholar of 18th-century British literature, first began editing the online encyclopedia in 2004. Though she first edited anonymously, Wadewitz later became a public face of Wikipedia and attempted to address the website's gender bias, and was quoted on the subject in the media. She died on April 8, 2014 after a fall while rock climbing in Joshua Tree National Park.

Video: Victor Grigas

The Papuan frogmouth (Podargus papuensis) is the longest bird in the frogmouth family. First described by Jean René Constant Quoy and Joseph Paul Gaimard in 1830, this species is found in subtropical or tropical moist lowland forests in Australia, Indonesia, and Papua New Guinea. This nocturnal bird feeds by hunting for insects, lizards, frogs, and small rodents on the ground.

Photograph: JJ Harrison

The poster for an American burlesque production, Bend Her, dating from circa 1900; this burlesque was a take on Lew Wallace's novel Ben-Hur, which had recently been adapted to stage by William Young.

Burlesque productions such as this were variety shows involving a blend of satire, performance art, music hall and adult entertainment such as stripteases. As with Victorian burlesque, the stories were often parodies of popular contemporary works. These shows, mostly featuring female performers, could be put on in cabarets, clubs, music halls, and theatres.

Poster: Courier Company; restoration: Adam Cuerden

Ellmau is a municipality in the Kufstein district of Sölllandl, Austria. This village, first recorded in the 12th century, is a popular resort in both winter and summer.

Photograph: Bernie Kohl

The first page of the original handwritten text of the United States Constitution, which took almost four months to draft and over three years to ratify. The first Constitutional Convention began on May 25, 1787, with a quorum at the Pennsylvania State House in Philadelphia to revise the Articles of Confederation. Instead the delegates wrote a new constitution, finishing on September 17 of that year, but its ratification by all 13 states was not completed until January 10, 1791. Since then 27 amendments have been made.

Read further: Page 2, Page 3, Page 4

Document: Constitutional Convention; scan: National Archives

A Diet Coke and Mentos eruption is a reaction between the carbonated beverage Diet Coke and Mentos mints that causes the liquid to spray out of its container. The mints cause nucleation that releases dissolved carbon dioxide so fast it pushes the liquid up and out of the bottle, in what has been described as an eruption or geyser. Though this was demonstrated on television as early as 1999, the reaction went viral in 2005, after Steve Spangler posted a video to YouTube.

Photograph: Michael Murphy