Tanzania, 1964. A touching moment between primatologist and National Geographic grantee Jane Goodall and young chimpanzee Flint at Tanzania's Gombe Stream Reserve. (Photo by Hugo van Lawick via National Geographic)

“If a man insisted always on being serious, and never allowed himself a bit of fun and relaxation, he would go mad or become unstable without knowing it”. – Herodotus. “You can discover more about a person in an hour of play than in a year of conversation”. – Plato. Photo: Mandalay, Burma. (Photo by Steve McCurry)

A Siberian eagle owl, which can grow up to 71cm tall, is among a collection of 60 birds of prey at SMJ Falconry near Oxenhope, West Yorkshire, England. (Photo by Charlotte Graham)

A juvenile leopard cat, seized by authorities during an anti-smuggling operation, is seen past suspected smugglers during a press conference announcing the seizure of trafficked exotic animals in Surabaya on March 27, 2019. Indonesian authorities said March 27 they had seized five komodo dragons and dozens of other animals being sold on Facebook, as the country battles to clamp down on the illegal wildlife trade. (Photo by Juni Kriswanto/AFP Photo)

A life-size replica of a Diplodocus dinosaur watches people coming out of the subway in the city center of Bochum, Germany, Monday, August 12, 2019. The exhibition, featuring models of 33 dinosaurs all around the city center, is in Bochum due to the discovery of an 316 million years old dinosaur track found in a stone pit in the city six years ago. (Photo by Martin Meissner/AP Photo)

Argentinian twin dancers Nicolas Filipeli and German Filipeli perform during the Tango Stage final competition at the Tango Dance World Championship in Buenos Aires on August 21, 2019. (Photo by Ronaldo Schemidt/AFP Photo)

A 180 degrees rotated photograph shows the shadows of Polina (L), a six-year-old Belarusian first grade school girl, and her father, cast on the street while on their way to Polina's first day of school, which marks the traditional start of the academic year, in Minsk, Belarus, 02 September 2019. The start of a new academic year in Belarus, officially called Day of Knowledge, is a festive day for all school and university students in the country. (Photo by Tatyana Zenkovich/EPA/EFE)

A fado singer smokes a cigarrette outside a fado house at the Alfama neighborhood in Lisbon on May 8, 2019. From fado sounds to Cape Verde mornas or bossa nova: the Lisbon nights, where musicians from all over the world meet, have largely inspired Madonna's new album, who has been in the Portuguese capital since 2017. (Photo by Patrícia de Melo Moreira/AFP Photo)