A general view of Edinburgh Castle on February 7, 2012 in Edinburgh, Scotland. The castle dominates the city skyline was built on top of an extinct volcano, and has had a human settlement on the castle site since 900BC. (Photo by Jeff J. Mitchell/Getty Images)

Titanoboa, meaning "titanic boa," is an extinct genus of snake that lived approximately 60–58 million years ago, during the Paleocene epoch, a 10-million-year period immediately following the dinosaur extinction event. The only known species is Titanoboa cerrejonensis, the largest, longest, and heaviest snake ever discovered, which supplanted the previous record holder, Gigantophis.

A full-scale model of the snake was unveiled at New York City's Grand Central station before the exhibit opens at the Smithsonian in Washington DC.

A leg of a “diablito” frog (Oophaga sylvatica) is photographed in a laboratory at a laboratory in the zoo of Cali, Colombia, on July 19, 2019. Colombia is the second country with the largest number of amphibians in the world after Brazil. More than 40% of amphibian species worldwide are in danger of extinction. (Photo by Luis Robayo/AFP Photo)

Frankie the Dinosaur, mascot of the United Nations Development Program “Don't Choose Extinction” visits Times Square spreading his climate-related message in New York on September 21, 2022. (Photo by Alex Kent/AFP Photo)

Belgian animal sculptor Emmanuel Janssens Casteels works at his desk next to a replica of a Smilodon, an extinct genus of machairodont felid, in his workshop in Prayssas December 3, 2014. Casteels' company OPHYS specializes in life-size reconstructions and the sculpting or moulding reproductions of animals and hyper-realist fossils. His reconstructions are exhibited in museums and theme parks. (Photo by Regis Duvignau/Reuters)

Among the fish populations that could be harmed by the Xayaburi dam in Laos is the critically endangered Mekong giant catfish, considered by the Guinness Book of World Records to be the world’s largest freshwater fish. The fish, which grows to 650 pounds and about 10 feet long, is only found in the Mekong River. It is migratory, moving between downstream habitats in Cambodia upstream to northern Thailand and Laos each year to spawn. Some experts fear the Xayaburi dam could block the migration and drive the giant catfish to extinction. (Photo by Courtesy of Zeb Hogan/University of Nevada, Reno)

A fisherman carries a large Pirarucu (Arapaima gigas) at the Piagacu-Purus Sustainable Development Reserve in Amazonas state, Brazil, on October 24, 2019. The pirarucu -a giant fish of the Amazon, that had been on the verge of extinction- can measure up to three meters and weigh more than 200 kilos. The soft and tasty white meat fish is nowadays served in renowned restaurants in Rio de Janeiro. (Photo by Ricardo Oliveira/AFP Photo)

An orphaned giraffe nuzzling a wildlife keeper at Sarara camp in Kenya, one of 70 pictures being sold by Prints for Nature (printsfornature.com) to raise money for work by the Conservation International charity. This giraffe was rehabilitated and returned to the wild, as a number of others have done before him. Right now, giraffe are undergoing what has been referred to as a silent extinction. Current estimates are that giraffe populations across Africa have dropped 40 percent in three decades, plummeting from approximately 155,000 in the late 1980s to under 100,000 today. (Photo by Ami Vitale/National Geographic)