South Korean teenagers participate in a warfare exercise as part of the Special Warfare Command's training course at a military base on August 4, 2011 in Seoul, South Korea. About 1,000 civilian volunteers including middle and high school students participated in the special force's four-day training programme to develop their spiritual and physical strength. (Photo by Chung Sung-Jun/Getty Images)

The Vietnam Slide Project was created by photo editor Kendra Rennick, who began collecting photo slides after a close friend lost her father, a Vietnam veteran. Her friend found a box of slides that her father had taken while in Vietnam and from there Rennick has continued to collect photographs that Vietnam veterans took during their tours of duty. Here: A photo taken from the collection of D.Thornton, who served in the First Air Cavalry division of the United States Army. (Photo by D.Thornton/The Vietnam Slide Project)

Military helicopters fly in formation above a billboard with a picture of China's late Chairman Mao Zedong during a training session for the upcoming parade marking the 70th anniversary of the end of World War Two, on the outskirts of Beijing, July 2, 2015. Troops from Russia and Mongolia will march together with Chinese forces in a parade in Beijing in September to commemorate the end of World War Two, the government and state media said on Thursday, confirming the first two foreign participants. (Photo by Jason Lee/Reuters)

Every year National Parks Week gives visitors a chance to celebrate the incredible woodland spaces around the UK. This year the National Parks Week runs from 28 July – 3 August and there are 10 national parks across England to explore. Each one has created a special event to celebrate the National Parks Week, from picnics and treasure hunt in the park to cycle rides, safari or outdoor art exhibition. (Photo by Diana Jarvis/VisitEngland)

A photographer is using a unique method to show the shift from day to night across famous cities in spectacular images. Daniel Marker-Moors' take on time-lapse photography – which he calls time slice – sees the photographer snap image after image, before combining them to create beautiful, vibrant works. His images usually focus on a point in the day with the most dramatic change in light, such as sunrise or sunset. Marker-Moors, from Los Angeles, begins by shooting hundreds and sometimes thousands of images from the same spot. Here: Chicago – 35 photographs, 15 minutes. (Photo by Daniel Marker-Moors/Caters News)

Bella Hadid smiles as she picks up a camera battery which a photographer dropped on the red carpet, before giving it back as she attends the “Ismael's Ghosts (Les Fantomes d'Ismael)” screening and Opening Gala during the 70th annual Cannes Film Festival at Palais des Festivals on May 17, 2017 in Cannes, France. (Photo by Pascal Le Segretain/Getty Images)

Actor George Clooney is arrested with his father Nick Clooney (2R) during a demonstration outside the Embassy of Sudan March 16, 2012 in Washington, DC. United to End Genocide, the Enough Campaign and Amnesty International held a rally to call on the United States and world leaders to stop the violence in South Sudan and prevent hundreds of thousands of people from starving. (Photo by Win McNamee/Getty Images)