A worker prepares the “Cutter Head” of the Port Tunnel boring machine for attachment to the tunneling machine on September 1, 2011 in Miami, Florida. The $45 million machine is longer than a football field and about as tall as a four-story building and it will carve the twin tunnels connecting Watson Island and Dodge Island. The the new $1 billion Port of Miami tunnel is expected to be completed in May of 2014. (Photo by Joe Raedle/Getty Images)

Workers at the World's Finest Chocolate company weigh what they hope will be a world record chocolate bar September 13, 2011 in Chicago, Illinois. The candy bar, weighing 12,190 pounds, standing nearly 3 feet high and measuring 21 feet long beat the previous record chocolate bar by more than a ton. (Photo by Scott Olson/Getty Images)

City workers transport a load of sandbags to be used in re-enforcing a levee gate past the Yazoo & Mississippi Valley Railroad Station May 11, 2011 in Vicksburg, Mississippi. The Mississippi river at Vicksburg is expected to crest at a record 58.5 feet. Heavy rains have left the ground saturated, rivers swollen, and have caused widespread flooding in Missouri, Illinois, Kentucky, Tennessee, and Arkansas. (Photo by Scott Olson/Getty Images)

Demonstrators confront riot police during clashes in central Brussels November 6, 2014. Tens of thousands of public and private sector workers, employees and trade union members demonstrated over austerity measures to be taken by the new Belgian government. (Photo by Francois Lenoir/Reuters)

A train drives along a field at a salt production site at the Sasyk-Sivash lake near the city of Yevpatoria, Crimea, November 14, 2017. A saltwater lagoon known as Lake Sasyk-Sivash on Ukraine's Crimea peninsula is the source of a rare resource: pink salt. The mineral is tinted by tiny algae that produce the pigment beta-carotene. Each autumn, seasonal workers collect thousands of tons of pink salt for processing and export. (Photo by Pavel Rebrov/Reuters)

Inspired by traditional Indian travelling photography studios, Arthur Crestani photographed the inhabitants of Gurgaon, a city built almost entirely by private companies. Arthur Crestani’s “Bad City Dreams” contrasts the glossy ideal sold by developers with urban reality. Here: Luxury Living Bhiwadi: “Sky Club on 18th Floor”. (Photo by Arthur Crestani/The Guardian)

North Korea has closed its borders in fear of the spread of the Ebola virus. But at a time when the secretive state was still welcoming tourists, former aid worker Andrew Macleod made the journey to the repressive nation. Andrew's holiday snaps and camera footage provide a unique insight into the reclusive country, where he came across deserted motorways, metro stations plastered with propaganda and attractive border guards. Here: a female traffic police officer in the snow in February 2013, in Pyongyang, North Korea. (Photo by Andrew Macleod/Barcroft Media)

Riot police walk past burning garbage containers during heavy clashes with demonstrators during a 24-hour strike on March 29, 2012 in Barcelona, Spain. Spanish workers staged a general strike to protest the government's latest labour reforms, which are designed to help Spain lower its deficit within EU limits. (Photo by David Ramos/Getty Images)