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)

Now celebrating its 40th year, Nikon Small World is widely regarded as the leading forum to recognize proficiency and photographic excellence of photography taken under the microscope. To select the winners, competition judges analyzed entries from all over the world covering subjects ranging from chemical compounds to up-close-and-personal looks at biological specimens. The 2014 winners will be revealed on October 30th. In 2014, the competition received over 1,200 entries from more than 79 countries around the world. (Photo by Dr. Igor Robert Siwanowicz/Nikon Small World 2014)

Reuters photographer Lucy Nicholson documented some of the migrant communities that live in Los Angeles. Los Angeles is a culturally thriving city and one of the most ethnically diverse in the United States, with a population that is 48.5 percent Latino and 11.3 percent Asian, according to a 2010 census. Immigration has become a hot button issue ahead of U.S. midterm elections on November 4, and despite arguments from the White House that legal migration benefits businesses, a recent opinion poll found most Americans believe migrants place a burden on the economy. (Photo by Lucy Nicholson/Reuters)

Hot Tub Cinema is an experience like no other. Combining relaxing hot tubs, great films and amazing spaces, it is a luxurious event that celebrates film in a fun and engaging way. Attendees can purchase whole tubs to share with friends or buy individual tickets to share with fellow hot tubbers. The tubs are cleaned, refilled and heated before every show. Popping-up throughout the year in London and around the UK, Hot Tub Cinema is also preparing to tour internationally in the near future. During the summer, we takeover rooftops in central London with astounding views across the city's inimitable skyline. For the autumn/winter we move indoors to continue the fun hidden away from the unpredictable weather.

In this photo taken on Sunday, February 15, 2015 a girl runs away from a “Mamuxarro” during the carnival, in the small town of Unanu, northern Spain. In the northern Spanish ancient village of Unamu, people dress up as “Mamuxarro”, folkloric figures in white with a red sash and a metal mask to cover their faces as they pursue townsfolk with sticks. According to custom, their “victims” (usually young women) must kneel and kiss the mamuxarro’s knee after he makes the sign of the cross on their forehead. (Photo by Alvaro Barrientos/AP Photo)

President Barack Obama watches as Joey Hudy (L), 14, from Phoenix, Arizona pumps the Extreme Marshmallow Cannon he invented, while touring student science fair projects on exhibit in the State Dining Room at the White House February 7, 2012 in Washington, DC. Obama hosted the second White House Science Fair celebrating the student winners of science, technology, engineering and math (STEM) competitions from across the country. (Photo by Molly Riley-Pool/Getty Images)

After finding the bricklaying business too full of ups and downs, this amazing young girl decided to take a shot at iron girdering for a change. She is Miss “Collie” Collier, a reporter for the Chicago Herald-Examiner. August 17, 1920. (Photo by Bettmann Archive/Getty Images)