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)

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)

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)

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)

A rose lies on a plastic sheet covering a victim of a Malaysian Airlines Boeing 777 plane which was downed on Thursday near the village of Rozsypne, in the Donetsk region July 18, 2014. International prosecutors investigating the downing of flight MH17 over eastern Ukraine in 2014 say the missile that hit the plane was fired from territory controlled by Russian-backed rebels. They said the missile launcher was brought into Ukraine from Russia. All 298 people on board the Boeing 777 died when it broke apart in midair flying from Amsterdam to Kuala Lumpur. The JIT investigation's findings are meant to prepare the ground for a criminal trial. (Photo by Maxim Zmeyev/Reuters)

A man stands between thousands of paper lanterns, which were displayed and lit up the precincts of the shrine, where more than 2.4 million war-dead are enshrined, during the Mitama Festival at Yasukuni Shrine in Tokyo, Japan July 13, 2016. “Mitama” is a respectful word that means “the soul of a dead person” in Japanese, and this “Soul Festival” honors just that. (Photo by Issei Kato/Reuters)