Felice Varini is a Swiss artist who was nominated for the 2000/2001 Marcel Duchamp Prize, known for his geometric perspective-localized paintings in rooms and other spaces, using projector-stencil techniques. According to mathematics professor and art critic Joël Koskas, “A work of Varini is an anti-Mona Lisa”.

The Prague astronomical clock, or Prague orloj, is a medieval astronomical clock located in Prague, the capital of the Czech Republic. The clock was first installed in 1410, making it the third-oldest astronomical clock in the world and the oldest one still working.

The Nicobar pigeon (Caloenas nicobarica) is a pigeon found on small islands and in coastal regions from the Nicobar Islands, east through the Malay Archipelago, to the Solomons and Palau. It is the only living member of the genus Caloenas and the closest living relative of the extinct dodo.

The bloodwood tree (Pterocarpus angolensis) is a deciduous tree with a high canopy, reaching about 15m in height and has dark bark. The red sap is used traditionally as a dye and in some areas mixed with animal fat to make a cosmetic for faces and bodies. It is also believed to have magical properties for the curing of problems concerning blood, apparently because of its close resemblance to blood. The name bloodwood for these trees stems from the dark red to brown sap that accumulates on wounds on the trunks.

Axel Erlandson (December 15, 1884 – April 28, 1964) was a Swedish American farmer who shaped trees as a hobby, and opened a horticultural attraction in 1947 advertised as "See the World's Strangest Trees Here," and named "The Tree Circus."
The trees appeared in the column of Robert Ripley's Believe It or Not! twelve times. Erlandson sold his attraction shortly before his death. The trees were moved to Gilroy Gardens in 1985.

A cenote is a natural phenomenon, a sinkhole in the Earth’s surface. The Yucatan Peninsula in Mexico has an estimated 7,000 cenotes because it is primarily made up of porous limestone. For millions of years, rainfall slowly ate away at the limestone and a huge system of underground caves and caverns was formed. Many filled with water from rain or from the underground water table. When the roof of a water filled cave collapses, a cenote is born. The water found in a cenote may be fresh water, salt water, or both. Structurally it may be completely open, like a lake, almost completely closed with just a small opening at the top, or somewhere in between.

Stemonitis axifera is a species of slime mold. It fruits in clusters on dead wood, and has distinctive tall reddish-brown sporangia, supported on slender stalks. The species was first described as Trichia axifera by Jean Baptiste François Pierre Bulliard in 1791. Thomas Huston MacBride transferred it to the genus Stemonitis in 1889. Stemonitis fasciculata and Stemonitis smithii are synonyms.