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)

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)

This undated image provided by World View shows World View capsule and balloon spacecraft that will rise to 100,000 feet above Earth for passengers to see the curvature of the planet and the blackness of space. Space tourism companies are employing designs including winged vehicles, vertical rockets with capsules and high-altitude balloons. While developers envision ultimately taking people to orbiting habitats, the moon or beyond, the immediate future involves short flights into or near the lowest reaches of space without going into orbit. (Photo by World View via AP Photo)

A protester gestures after he saw a dead protester in Kampala, Uganda February 15, 2016. At least one person has been killed in Uganda's capital Kampala as police clashed with opposition supporters after briefly detaining a top presidential candidate twice as he tried to hold campaign rallies days before a general election. Several people were wounded in the clashes as police fired bullets and tear gas while opposition supporters hurled rocks and erected street barricades in the capital's Wandegeya suburb, witnesses said according to a Reuters news agency report. (Photo by Goran Tomasevic/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 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)

A man carries an injured woman in a site hit by what activists said were airstrikes carried out by the Russian air force in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria January 9, 2016. At least 70 people died in what activists said where four vacuum bombs dropped by the Russian air force in the town of Maaret al-Numan; other air strikes where also carried out in the towns of Saraqib, Khan Sheikhoun and Maar Dabseh, in Idlib. (Photo by Khalil Ashawi/Reuters)

“Kumbh Mela is a mass Hindu pilgrimage in which Hindus gather at the Ganges river. The normal Kumbh Mela is celebrated every 3 years, the Ardh (half) Kumbh Mela is celebrated every six years at Haridwar and Prayag, the Purna (complete) Kumbh takes place every twelve years, at four places (Prayag (Allahabad), Haridwar, Ujjain, and Nashik). The Maha (great) Kumbh Mela which comes after 12 “Purna Kumbh Melas”, or 144 years, is held at Allahabad.

The last Ardh Kumbh Mela was held over a period of 45 days beginning in January 2007, more than 70 million Hindu pilgrims took part in the Ardh Kumbh Mela at Prayag, and on January 15, the most auspicious day of the festival of Makar Sankranti, more than 5 million participated. The previous Maha Kumbh Mela, held in 2001, was attended by around 60 million people, making it at the time the largest gathering anywhere in the world in recorded history”. – Wikipedia

Photo: Sadhus (holy men) smoke at their camp near the ritual site at Sangam, the confluence of the Ganges, Yamuna and mythical Saraswati rivers during the Ardh Kumbh Mela festival (Half Pitcher festival) January 18, 2007 in Allahabad, India. Millions of Hindu pilgrims have flocked to the largest religious gathering in the world which lasts for 45 days in northern India. The festival commemorates the mythical conflict between gods and demons over a pitcher filled with the “nectar of immortality”. Devotees believe that taking a holy dip in the Ganges at this time washes away their sins and paves the path to salvation. (Photo by Mario Tama/Getty Images)