Marius was a male giraffe living at Copenhagen Zoo. Though healthy, he was genetically unsuitable for future captive breeding, as his genes were over-represented in the captive population, so the zoo authorities decided to euthanize him. Despite several offers to adopt Marius and an online petition to save him, he was killed on 9 February 2014. His body was then dissected and necropsied in a public educational class and then fed to the zoo's lions. The event received worldwide media coverage and generated responses from several organisations and individuals, including death threats to staff at the zoo.

Copenhagen Zoo is a zoological garden in Copenhagen, Denmark. Founded in 1859, it is one of the oldest zoos in Europe and is a member of EAZA. It comprises 11 hectares and is located in the municipality of Frederiksberg, sandwiched between the parks of Frederiksberg Gardens and Søndermarken. With 1,571,331 visitors in 2019 it is the most visited zoo and one of the most visited attractions in Denmark. The zoo is noted for its new Elephant House designed by British architect Sir Norman Foster. The zoo maintains and promotes a number of European breeding programmes.