A woman wearing a scarf to cover her face looks on as she waits for a passenger bus on a smoggy morning in New Delhi, India, November 8, 2017. The Great Smog of Delhi is an ongoing severe air-pollution event in New Delhi and adjoining areas in the National Capital Territory of India, in November 2017. Air pollution at this time peaked on both PM 2.5 and PM 10 levels. It has been reported as one of the worst levels of air quality in Delhi since 1999. (Photo by Saumya Khandelwal/Reuters)

Grave diggers wearing personal protective equipment (PPE) walk away after burying a person, who presumably died of the coronavirus disease (COVID-19), in the special purpose section of a graveyard on the outskirts of Saint Petersburg, Russia on May 13, 2020. (Photo by Anton Vaganov/Reuters)

“Show Time”. It's a normal behavior of mantis. They're doing defence. When they're afraid of; raising their arms and spreading their wings. They looks like smiling dancer. Photo location: Nicosia, Cyprus. (Photo and caption by Hasan Baglar/National Geographic Photo Contest)

“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)

The car driven by Scott Dixon, of New Zealand, goes over the top of Jay Howard, of England, in the first turn during the running of the Indianapolis 500 auto race at Indianapolis Motor Speedway, Sunday, May 28, 2017, in Indianapolis. (Photo by Marty Seppala/AP Photo)

A camel rests at a fuel station in the Judean desert near the West Bank city of Jericho January 11, 2015. Reuters photographers from Mali to Mexico have shot a series of pictures of fuel stations. Whether it is plastic bottles by the roadside in Malaysia or a futuristic forecourt in Los Angeles, fuel stations help define our world. Oil prices steadied above $48 a barrel on Tuesday, recovering from earlier losses as the dollar weakened against the euro. Oil prices have dropped nearly 60 percent since peaking in June 2014 on ample global supplies from the U.S. shale oil boom and a decision by OPEC to keep its production quotas unchanged. (Photo by Baz Ratner/Reuters)

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)

Two dancers pass each other as they compete in a heat during the All Scotland Championships in Irish Dancing at the Royal Concert Hall in Glasgow, Scotland. The championships attract over 2000 dancers from more than 300 dance schools, from countires such as North America, South Africa, Australia and Russia. (Photo by David Moir/Reuters)