The Tribute in Light is seen behind the Empire State Building on September 10, 2011 in New York City. The Tribute in Light is an art installation honoring those who perished in the 9/11 attacks. New York City and the nation are preparing for the tenth anniversary of the terrorist attacks on lower Manhattan which resulted in the deaths of 2,753 people at the World Trade Center. (Photo by Mario Tama/Getty Images)

German flying ace Baron Manfred von Richthofen (1892–1918) also known as The Red Baron with his dog Moritz, circa 1916.

Ricardo Azevedo rides his Honda NX 200 motorbike, which he converted to be powered by water, in Salto, northwest of Sao Paulo, Brazil, August 6, 2015. The Sao Paulo civil servant built the motorbike, which can cover up to 500 kilometres (311 miles) fuelled by just one litre of water. Dubbed “Moto Power H2O” the bike is powered by the process of electrolysis, which breaks the water molecule down into its constituent elements. (Photo by Nacho Doce/Reuters)

Belly dancer Nagwa Fouad sailing on the river Nile, 1972. Egypt is one of 23 countries represented at the Dubai Photo Exhibition, showing off photography that dates to the 1920s. Dubai Photo Exhibition is in various venues of Dubai’s design district from 16-19 March. (Photo by Farouk Ibrahim)

Young acutus crocodile are pictured at Panagator, a sustainable crocodile farm, on the outskirts of Panama City September 11, 2015. Gladys Vallarino, owner of the farm and of a specialty boutique shop selling items made from crocodiles, says the farm looks after more than 19,000 Acutus and Fuscus species of crocodiles and donates five percent of its crocodiles annually to the Panamanian authorities to be put into the wild, in accordance with the regulations of the CITES (Convention of International Trade in Endangered Species). The handmade fashion items sell for $200 to $3,000. (Photo by Carlos Jasso/Reuters)

Veterinarian William Guerra Neto (2nd R) and an assistant take measurements of two Amazonian manatees who are being rehabilitated after sustaining injuries from hunting and fishing nets at the Center of Amazonian Manatees at Amana Lake in Maraa, Amazonas state, Brazil, September 21, 2015. (Photo by Bruno Kelly/Reuters)

Smokes rises from a fire as a Palestinian protester takes cover during clashes with Israeli troops near the Jewish settlement of Beit El, near the West Bank city of Ramallah October 9, 2015. (Photo by Mohamad Torokman/Reuters)