In this aerial view the officers' building and an auditorium stand at the former Soviet military base on January 26, 2017 in Wuensdorf, Germany. Wuensdorf, once called “The Forbidden City”, was the biggest base for the Soviet armed forces in communist East Germany from 1945 until the last Soviet troops left in the early 1990s following the end of the Cold War and the reunification of Germany. (Photo by Sean Gallup/Getty Images)

Son doong cave is a cave in Phong Nha-Kẻ Bàng National Park, Bố Trạch district, Quảng Bình Province, Vietnam. Currently the biggest known cave in the world, the cave is located near the Laos-Vietnam border. Inside is a large, fast-flowing underground river.
In early August 2013, the first tourist group explored the cave on a guided tour at a cost of US$3,000 each. The group had six members from Australia, Norway, Russia and USA and spent 7 days and 6 nights for the tour. Next exploration trips will be arranged.

Karim Nafatni is an Airline Captain and photography enthusiast. He seriously got into the Art when he got his first DSLR 3 years ago. Addicted to height and fan of architecture,he climbs the highest skyscrapers of Dubai to take his pictures ,sometimes more than 300 meters above ground. As the top of the biggest buildings in the world is not high enough for him,he carries his camera with him during work to document his daily routine in"his Office" and shoots from his flight deck.

A woman in a maid costume serves customers the Maid Coffee Shop in the Akihabara District October 23, 2005 in Tokyo, Japan. The Akihabara District is known as the world's biggest electrical appliance and equipment town, but recently this area has also became famous for having many shops delivering products and healing services by employees in the costume of maids and animation characters. Some popular shops include coffee, hair salon and massage shops where females deliver services dressed as maids. (Photo by Koichi Kamoshida/Getty Images)

Workers work inside a new Antonov airplane at the Antonov aircraft plant in Kiev, Ukraine, September 7, 2015. State-run aircraft maker Antonov built more than 22,000 units of more than one hundred types and modifications of passenger, transport and special-purpose aircraft, including the world's biggest cargo plane Antonov-225 (Mriya), according to the company's official website. (Photo by Gleb Garanich/Reuters)

A life-size sculpture of a pianist, made of approximately 210,000 matches and weighs around 100 kilograms, is seen in Tomislav Horvat's studio in Podturen, Croatia, October 27, 2016. For the last ten years, Horvat has built sculptures made from matches. This is his biggest sculpture to date that took him some 30 months to build. (Photo by Antonio Bronic/Reuters)

A Colombian air force helicopter retrieves the bodies of victims from the wreckage of a plane that crashed into the Colombian jungle with Brazilian soccer team Chapecoense onboard near Medellin, Colombia, November 29, 2016. The chartered plane was carrying a Brazilian soccer team to the biggest match of its history when it crashed into a Colombian hillside and broke into pieces, killing 75 people and leaving six survivors, Colombian officials said Tuesday. (Photo by Jaime Saldarriaga/Reuters)

Employees of the Park Royal resort wait for a shuttle to take them to work early in the morning on April 2, 2015 in Acapulco, Mexico. Despite problems with cartel violence Semana Santa is one of the biggest tourist weeks of the year in Acapulco, a city whose entire economy depends on tourism, and officials expect around 350,000 mostly Mexican visitors this week. (Photo by Jonathan Levinson/The Washington Post)