Vietnam’s Son Doong cave, the largest in the world, could hold a 40-story skyscraper inside. The pristine ecosystem has its own river and jungle. Despite its size, Son Doong wasn’t discovered until 1991. It was lost again for nearly two decades and was fully explored for the first time in 2009. (Photo by Jason Speth/HuffPost)

A young YPJ recruit (in pink) arrives to the training base for her first day in training near Derek City, Syria. The YPJ schedule is demanding and requires discipline – new soldiers in training get about 6 hours of sleep a night and wake up at 4 AM to begin exercising; afterwards, their day consists of a full schedule of drills and classroom lessons. Before joining the YPJ many of the girls had never participated in physical activity or sports before. (Photo by Erin Trieb/NBC News)

Undated UK Ministry of Defence handout photo of an RAF Tornado GR4 which has been painted in Gulf War “desert pink” paint scheme to honour the aircraft type's almost continuous operational service since the Royal Air Force helped liberate Kuwait from Saddam Hussein's forces, taken by SAC Rose Buchanan, which has been shortlisted for the general public to pick their favourite RAF Image of the Year. (Photo by SAC Rose Buchanan/MoD Crown Copyright/PA Wire)

The red-footed booby is the smallest of all boobies at about 70 centimetres (28 in) in length and with a wingspan of up to 1 metre (3.3 ft). It has red legs, and its bill and throat pouch are coloured pink and blue.

Victoria's Secret angels Adriana Lima, Candice Swanepoel, Alessandra Ambrosio and Miranda Kerr arrive at the 2011 Victoria's Secret SWIM Collection Pink Carpet Event hosted by VS Angels at Club L on March 30, 2011 in Los Angeles, California. (Photo by Jerod Harris/Getty Images for Victoria's Secret)

“Yokohama Hakkeijima Sea Paradise is an amusement park consisting of an aquarium, shopping mall, hotel, marina and amusement rides. It is located in Kanazawa-ku, Yokohama, Japan. It opened for business on May 8, 1993”. – Wikipedia

Photo: Shoal of sardines and sharks swim in a tank at Yokohama Hakkeijima Sea Paradise on March 19, 2009 in Yokohama, Japan. (Photo by Junko Kimura/Getty Images)

Parade Marshall Captain Gary Tomlin gives a command during a Remembrance Sunday parade through Fulham in West London, Britain November 8, 2009. Every year in November, villages, towns and cities across Britain honour those who have lost their lives in war on Remembrance Sunday. While Queen Elizabeth leads tributes at a national service of remembrance at The Cenotaph war memorial in central London, various neighbourhoods also hold their own local marches and memorials. (Photo by Kevin Coombs/Reuters)

“Start your day with a good breakfast together”, 2009. “There was this trend of eating sushi from a woman’s naked body. So when I found the perfect papaya, I knew exactly how to shoot it”. (Photo by Pixy Liao/The Guardian)