Men rest after salvaging metal on the 30th floor of the “Tower of David” skyscraper in Caracas February 3, 2014. A 45-storey skyscraper in the center of Venezuela's capital Caracas is a slum, probably the highest in the world. Dubbed the “Tower of David”, the building was intended to be a shining new financial center but was abandoned around 1994 after the death of its developer – banker and horse-breeder David Brillembourg – and the collapse of the financial sector. (Photo by Jorge Silva/Reuters)

At the dead of night, the photographer – known to his Instagram followers as Dark Cyanide – heads out to look for hidden gems, like abandoned stations, provisions and tunnels. His intriguing images feature vibrant streaks, graffiti, and tight framing – and by adding individuals to some to some of shots, he is also able to depict the incredible scale of some of the tunnels. Here: Unnamed subway track in New York City. (Photo by Dark Cyanide/Caters News)

Katjinga, a Rhodesian ridgeback dog who lives on a 20-acre farm in Germany, adopted an abandoned pot-bellied piglet in August 2009. The tiny black piglet, named Paulinchen, had been so small at birth that her mother likely overlooked it. Katjinga's owner, Roland Adam, found the piglet alone and cold and brought it to his 8-year-old dog. (Photo by Fame Pictures)

The extravagant residence Castello di Sammezzano sits on top of a hill in Tuscany, Northern Italy. Originally it was built in the Moorish style in 1605 for Ximenes d'Aragona and then re-designed between 1853 and 1889. After the war the castello was used as a luxury hotel until closure in the mid to late 1990's. It was abandoned until April 2012 when the FPXA committee was formed, aiming to promote and enhance the castle.

Patsy Gibbons takes his two rescue foxes, Grainne and Minnie (unseen), for a walk in Kilkenny, Ireland April 25, 2016. Gibbons nursed the foxes back to health after they were found abandoned as injured cubs, and they have stayed with him since. (Photo by Clodagh Kilcoyne/Reuters)

Photojournalist Lauren DeCicca met three Thai families who have created makeshift homes from abandoned aeroplanes in a vacant lot in east Bangkok. This vacant lot on Ramkhamhaeng Road in east Bangkok is locally known as the “Airplane Graveyard”. Here: A child perches in one of the fuselages. (Photo by Lauren DeCicca/The Guardian)