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)

A bodyboarder rides a wave at Mackenzies Bay on May 1, 2011 in Sydney, Australia. A strong east-south-east swell has developed along the NSW coastline with waves between 6ft and 8ft expected to hit the coast for much of the weekend and into next week. (Photo by Cameron Spencer/Getty Images)

East Berliners crossing into the West Berlin on November 11, 1989 at the Potsdamer Platz, Germany. (Photo by Kai Wiedenhoefer)

People view the sunrise scene at the Bund in Shanghai, east China, January 1, 2017. (Photo by Wang Hechun/Xinhua/Barcroft Images)

People watch an eruption of the South East volcano of Etna is seen from the village of Nicolosi, Italy February 10, 2022. (Photo by Antonio Parrinello/Reuters)

Mangrove in Walakiri Beach after Sunset in East Sumba, Indonesia in 2018. (Photo by Sarubabel Malau/Rex Features/Shutterstock)

Joshua Patino stands on a ladder to put finishing touches on a giant dinosaur exhibit at PAX East in the Boston Convention and Expo Center, Thursday, April 21, 2016, in Boston. PAX East, an annual celebration of gaming culture, is expected to draw tens of thousands of visitors Friday through Sunday. It's a place where serious gamers can preview unreleased video games and devices, compete in tournaments, hear live music and meet others for whom gaming is a way of life. (Photo by Elise Amendola/AP Photo)

Tattoo enthusiast Lauren Brock poses to display her body art work during the International London Tattoo Convention in east London, Britain September 26, 2015. (Photo by Neil Hall/Reuters)