Two hippopotamus are fed with pumpkins at the Hanoi Zoo, in Hanoi, Vietnam, 25 October 2018. The zoo has been the home for more than 800 animals of over 90 different species, including three hippopotamus, since it was built in 1976. (Photo by Luong Thai Linh/EPA/EFE)

A Japanese white-eye is seen on a branch of cherry blossoms at Kyoto Imperial Palace on March 26, 2010 in Kyoto, Japan. (Photo by Akihiro I/Getty Images)

Clouds gather as walkers pause atop a ridge in Mountain View, California January 7, 2016. (Photo by Noah Berger/Reuters)

In this Friday, March 28, 2014 photo, singers of the Moranbong Band, Jong Su Hyang, foreground, and Pak Mi Kyong, left perform on their stage in Pyongyang, North Korea. Step aside, Sea of Blood Opera. North Korean leader Kim Jong Un's favorite guitar-slinging, miniskirt-sporting girl group, the Moranbong Band, is back. And these ladies know how to shimmy. (Photo by Jon Chol Jin/AP Photo)

These stunning coloured images show detailed x-ray images of everything from skulls to light bulbs. Artist Paula Fontaine, from Westminster Massachusetts, created the images using a process called digital map painting. To create the images the x-ray emission source – the head of the machine on an arm which focuses the beam – is placed over the object. Paula then retreats behind a shielded screen before activating the x-ray exposure. Here: Brain storm, conceptual composite X-ray. (Photo by Paula Fontaine/Barcroft Media)

Dogs of a visitor pass by the grave of Marquise and Tony, the two small dogs of the Princess Lobanoff de Rostoff at the cimetiere des chiens (Cemetery of dogs) ahead of the commemoration of All Saints Day at the Montmartre cemetery in Asnieres, northern Paris, France, October 30, 2016. (Photo by Charles Platiau/Reuters)

Japanese women wearing kimonos take a selfie as they attend their Coming of Age Day celebration ceremony at Toshimaen amusement park in Tokyo, Japan on January 14, 2019. Coming of Age Day is a Japanese holiday held every January to celebrate people who have reached 20 – the official age of adulthood in Japan. (Photo by Issei Kato/Reuters)

Italian Air Force's aerobatic demonstration team, the Frecce Tricolori leave colourful vapour trails as they fly over the Altare della Patria monument on Republic Day (Festa della Repubblica) in Rome, Italy, 02 Jun 2017. The anniversary marks the founding of the Italian Republic in 1946. (Photo by Massimo Percossi/EPA)