The fourth annual BigPicture Natural World Photography Competition aims to celebrate the diversity of life on Earth, and encourages people to protect and conserve it. Here: “The Salmon Catchers”. Terrestrial Wildlife. To capture this view of a mother grizzly bear and her cub, photographer Peter Mather set up a camera trap on a log that he knew the bears tended to traverse while fishing for salmon, in the Yukon River watershed in Canada. (Photo by Peter Mather/BigPicture Natural World Photography Competition 2017)

A supporter of the presidential candidate for the Honduran Opposition Alliance Against the Dictatorship for the past election, Salvador Nasralla, lies on the street in front of police officers during a demonstration against the contested re-election of President Juan Orlando Hernandez, in Tegucigalpa, Honduras on January 21, 2018. (Photo by Orlando Sierra/AFP Photo)

A child parades on a float during the Bun Festival on May 25, 2015 in Hong Kong, Hong Kong. One of Hong Kong's most colourful cultural celebration event, Cheung Chau Bun Festival, will be staged on 25 May 2015 (Monday) till 26 May 2015 midnight (Tuesday). This festival has over 100 years of history. Every year, thousands of people descend upon the tiny island for The Piu Sik (Floating Colours) Parade, Lucky Bun (Ping On Bun) and The Bun Scrambling Competition, the ancient custom during the festival. (Photo by Lam Yik Fei/Getty Images)

The Museum of Feelings doesn't really have “exhibits" in the conventional sense; rather, visitors move from one themed alcove to another, five in total, each with its own distinctive aroma. The “Optimistic Room," bathed in vivid pink and purple light, is little more than a lightshow, with patrons using small reflective panels to bounce light around the room. Here: People interact in the “optimistic” room at the Museum of Feelings, a pop-up installation in New York, December 15, 2015. (Photo by Stephanie Keith/Reuters)

Sustainable development goal target 12.5 is to reduce waste. But with a planet increasingly dependent on technology, is that even possible? As of today, over 30m tonnes of electronic waste has been thrown out so far this year, according to the World Counts. Most e-waste is sent to landfills in Asia and Africa where it is recycled by hand, exposing the people who do it to environmental hazards. Kai Loeffelbein’s photographs of e-waste recycling in Guiyu, southern China show what happens to discarded computers. (Photo by Kai Loeffelbein/laif Agentur)

A heavily tattooed Japanese woman poses for photographs near Asakusa Temple during the third and final day of Sanja Festival, on May 20, 2018 in Tokyo, Japan. Sanja Festival is one of Japan's major festivals and is held annually in the Asakusa area of Tokyo. (Photo by Carl Court/Getty Images)

Members of the “Exit Point” amateur rope-jumping group stage a performance as they jump from a 44-metre high (144-ft) waterpipe bridge in the Siberian Taiga area outside Krasnoyarsk, November 3, 2013. Fans of rope-jumping, a kind of extreme sport involving a jump from a high point using an advanced leverage system combining mountaineering and rope safety equipment, marked the end of the group's jumping season and recent Halloween festivities. (Photo by Ilya Naymushin/Reuters)

“Burning Man is a week-long annual event held in the Black Rock Desert in northern Nevada, in the United States. The event starts on the Monday before the American Labor Day holiday, and ends on the holiday itself. It takes its name from the ritual burning of a large wooden effigy on Saturday evening. The event is described by many participants as an experiment in community, radical self-expression, and radical self-reliance”. – Wikipedia

Photo: A fireball billows up from a 52-foot tall wooden man as it goes up in flames September 2, 2000 during the15th annual Burning Man festival in the Black Rock Desert near Gerlach, Nevada. Despite high winds, dust storms, and a bit of rain, some 27,000 people camped out on a remote desert playa, or dry lake, for the week-long counter-cultural celebration of art and “radical self-expression”. (Photo by David McNew/Newsmakers)