Antek Marciniec holds onto a slackline after falling off as he highlines between two cliffs at Diamond Bay on December 21, 2014 in Sydney, Australia. Slacklining is a balance sport in which participants walk on a flat nylon webbing anchored between two points with the tension adjusted to allow for slack, providing an experience similiar to that of walking on a trapmoline. Highlining is a style of slacklining where the two anchor points are set up with significant elevation from the ground or water. (Photo by Cameron Spencer/Getty Images)

The newly-discovered gaseous planet Kepler-16b orbits it's two stars. NASA's Kepler Mission discoverd the world orbiting two Stars, the larger a K dwarf and the smaller a red dwarf. (Photo by NASA/JPL-Caltech/T. Pyle via Getty Images)

James Doran has created two epic dragon sculpture. The first, perched on a dead tree, is called ‘The Wyvern in the Baobabs’ (a wyvern is a type of dragon with two legs and two wings). The other, ‘Wyvern’s Folly,’ is perched on a gazebo made from reclaimed steel and recycled water bottles.

Canadian-Israeli film director Simcha Jacobovici holds two nails during a press conference on April 12, 2011. Jacobovici believes that the two nails discovered in a Jerusalem cave were used in the crucifixion of Jesus Christ. Jacobovici claims that the nails were tracked to an archeology laboratory in Tel Aviv, and though cannot be 100 per cent certain that they are the nails used in the crucifixion of Jesus, he claims if “you put two and two together and they seem to imply that these are the nails”. Experts at the Israel Antiquities Authority though cast doubt on Jacobovici's claims, and suggest that nails are commonly found in such locations. (Photo by Lior Mizrahi/Getty Images)

A fight between two female musk oxen, Norway, 2021. The image was captured in Norway’s Dovrefjell national park, where the musk ox (Ovibos moschatus) was reintroduced several years ago for its conservation. It is normal for males of this species to engage in fierce battles during the mating season but unusual for two females. (Photo by Miquel Angel Artús Illana)

Two men using an electric power saw to fell a tree circa 1940's. (Photo by Keystone View/FPG/Getty Images)

Soldiers, including two recruits who have brought some chickens, at Victoria prepare to board the train for the battle front. (Photo by Hulton Archive/Getty Images)

Two sheep fight in a competition in Zhangjiakou, Hebei province, China on August 1, 2017. (Photo by Reuters/China Stringer Network)