Secret arrive during the 1st Gaon Chart K-POP Awards at Blue Square on February 22, 2012 in Seoul, South Korea. (Photo by Chung Sung-Jun/Getty Images)

Only after World War II did the secret spill: Ōkunoshima, located in the Inland Sea of Japan between Hiroshima and Shikoku, was the top-secret site for manufacturing chemical warfare. When the factories were closed down, a number of exotic wild rabbits were seen freely roaming the island. They were assumed to have been the test subjects for the chemical weapons, which the military failed to eradicate when the factory was demolished.

British Institute of Radiology artist-in-residence Hugh Turvey creates images with x-rays to reveal the hidden contents of wrapped presents.

Coulpe in bed, secret lover hiding. (Photo by Peter Cade/Getty Images)

Victoria's Secret Angel Martha Hunt celebrates the 2015 What Is s*xy? List in San Diego on September 26, 2015 in San Diego, California. (Photo by Joe Scarnici/Getty Images for Victoria's Secret)

Victoria's Secret model Adriana Lima poses with her Madame Tussaud's wax likeness at a reveal event at the Victoria’s Secret store in Herald Square in the Manhattan borough of New York November 30, 2015. (Photo by Brendan McDermid/Reuters)

Janelle Monae (L) and Taraji P. Henson pose with the SAG Award for Outstanding Cast in a Motion Picture award for “Hidden Figures”, during the 23rd annual Screen Actors Guild Awards ceremony at the Shrine Exposition Center in Los Angeles, California, USA, 29 January 2017. (Photo by Paul Buck/EPA)

A hand out picture released by Queensland police on November 7, 2016 shows a police officer taking care of a baby koala in Brisbane Australian police made one of their more unusual finds when they uncovered a baby koala hidden in the bag of a woman they stopped in the street. (Photo by AFP Photo/Queensland Police)