A robin perches on a spade handle in a garden on a rainy day in Lixwm, north Wales. Researchers said this week that when European robins are subjected to human-produced noise, their behaviour changes. (Photo by DGDImages/Alamy Live News)

Fifty years ago, as France exploded in mass protests, words scrawled on the walls of the Sorbonne summed up the revolutionary zeal of the time: “Run free, comrade, we’ve left the old world behind!”. Sexual liberation, artistic creativity and anti-capitalism were the order of the day. For those who were there, it was an unforgettable time. Here: A wounded student is transported by first-aid workers during riots on the Boulevard Saint-Michel, Paris, France on May 6, 1968. (Photo by Gökşin Sipahioğlu/SIPA Press)

A brown-hooded kingfisher sits on a branch with a freshly caught frog in it's beak. Riaan Marais who took the photo said, “We were doing a boat safari on the Rufiji river in Selous Game Reserve, Tanzania when I spotted the bird with the frog on an overhanging branch on the river bank. It most probably caught the frog in the reeds along the river’s edge as this is where these frogs stay. The kingfisher must have caught the Common Reed Frog just before I took the image, as the frog was still alive, I had a brief moment to take the image before the bird flew off with the frog”. (Photo by Riaan Marais/Solent News and Photo Agency)

Londoners enjoying the magnificent sight of sun setting perfectly in the middle of London Eye as seen from Greenwich Park in London, England on the warmest day of the year on April 19, 2018. (Photo by London Viewpoints/Rex Features/Shutterstock)

Vehicles pass through the heavy fog and air pollution that cover Skopje valley in the early morning, in Skopje, The Former Yugoslav Republic of Macedonia, 14 December 2017. According to media reports, Skopje is considered one of the most polluted cities in the world. (Photo by Georgi Licovski/EPA/EFE)

An artist gets ready backstage to perform an Indian art form of dance called “Ottamthullal” at the annual eight-day long Vrischikolsavam festival, which features a colourful procession of decorated elephants along with drum and trumpets concerts, at Sree Poornathrayeesa temple in Kochi, India, December 7, 2018. (Photo by Sivaram V/Reuters)

A photojournalist is silhouetted by the sunset as a lightning strike at a resort affected by Saturday's tsunami in Carita, Indonesia, Tuesday, December 25, 2018. Christmas celebrations traditionally filled with laughter and uplifting music were replaced by somber prayers for tsunami victims in an area hit without warning following a volcanic eruption, leaving hundreds of people dead and thousands homeless in disaster-prone Indonesia. (Photo by Fauzy Chaniago/AP Photo)

A woman takes a selfie in front of a sculpture of a rooster that local media say bears resemblance to U.S. President-elect Donald Trump, outside a shopping mall in Taiyuan, Shanxi province, China December 30, 2016. (Photo by Jon Woo/Reuters)