A tour group wanders through block 7 of Eastern State Penitentiary in Philadelphia, Pennsylvania April 30, 2014. Opened in 1829, with the original corrective system of “confinement in solitude with labor”, the penitentiary housed about 75,000 inmates in its 142 years of operation. At Eastern State reunions, former inmates, staff and guard gather to share memories and trade stories and get a chance to describe their experiences in question-and-answer sessions with the public. (Photo by Mark Makela/Reuters)

A firefighter holds a red panda (Ailurus fulgens) from its tail while removing it from a tree at a residential area in Kunming, Yunnan province, July 3, 2014. The animal was spotted in the residential area and was brought down from the tree after residents reported its sighting to the police, local media reported. (Photo by Reuters/Stringer)

An Ambassador car, licensed as taxi rolls past other vehicles through a busy road in Kolkata, india, Monday, May 26, 2014. India's oldest car factory has abruptly suspended production of the hulking Ambassador sedan that has a nearly seven-decade history as the car of the Indian elite. (Photo by Bikas Das/AP Photo)

Two men standing on a high catwalk, surveying the construction of the Brooklyn Bridge, with Manhattan in the background, New York City, 1877. (Photo by Museum of the City of New York/Archive Photos/Getty Images)

Models promote a condom brand at the first Shenzhen s*x Culture Festival on September 21, 2007 in Shenzhen of Guangdong Province, China. The festival aims to increase awareness about reproductive health and popularise s*x education. (Photo by China Photos/Getty Images)

“Falling Back To Earth” promises to be both spectacular and meditative, and presents a beautiful, thought-provoking vision of our relationship with the earth and with each other. (Photo by Dave Hunt/EPA)

Daniel Ricciardo performs alongside Michael Kneightley in an RAAF F/A-18 Hornet at RAAF Base in East Sale, Victoria, Australia on March 12th, 2014. (Photo by Andy Green/Red Bull Content Pool)