The possible surface of TRAPPIST-1f, one of seven newly discovered planets in the TRAPPIST-1 system that scientists using the Spitzer Space Telescope and ground based telescopes have discovered. (Photo by Reuters/NASA/JPL-Caltech)

A mural signed by “TV Boy” and depicting Pope Francis and U.S. President Donald Trump kissing, is seen on a wall in downtown Rome, Italy on May 11, 2017. (Photo by Tony Gentile/Reuters)

The National Geographic Photo Ark is a travelling exhibition of photographer Joel Sartore’s quest to create a photo archive of biodiversity around the world. So far, Sartore has captured studio portraits of more than 6,000 species – a number that he hopes to double. On 1 July, the ark will open at Melbourne zoo – the first time it has been exhibited in the southern hemisphere. More than 50 portraits will be on display, including many of Australian endangered animals being protected by programs at the zoo itself. These captions have been edited from text supplied by Melbourne zoo. Here: Barking owl. (Photo by Joel Sartore/National Geographic Photo Ark/The Guardian)

Durga Kami, 68, who is studying tenth grade at Shree Kala Bhairab Higher Secondary School, walks with his classmate Sagar Thapa, 14, as they head to school in Syangja, Nepal, June 5, 2016. (Photo by Navesh Chitrakar/Reuters)

A Muslim boy takes part in Friday prayers on a street outside a mosque in Mumbai, India, June 24, 2016. (Photo by Shailesh Andrade/Reuters)

A hippopotamus performs during a show at the circus in Krasnoyarsk, Siberia, Russia, July 7, 2016. (Photo by Ilya Naymushin/Reuters)

An Indian artists uses sparkles to decorate statues of the Hindu god Lord Ganesh ahead of the forthcoming Ganesh Chaturthi festival at a workshop in Hyderabad on August 29, 2016. The statues are being prepared for the Ganesh Chaturthi festival a popular eleven-day long Hindu religious festival in India which will be celebrated from September 5 to 15. (Photo by Noah Seelam/AFP Photo)

George Harrison of the Beatles sits cross-legged with his musical mentor, Ravi Shankar of India, a sitar virtuoso, in Los Angeles, August 3, 1967, as Harrison explains to newsmen that Shankar is teaching him to play the sitar, a 25-stringed guitar-like instrument. Harrison said “Indian music makes God come through in a spiritual way”. (Photo by AP Photo)