Photochromes are vibrant and nuanced prints hand-coloured from black-and-white negatives. Created using a process pioneered in the 1880s, these images offer a fascinating insight into the world when colour photography was still in its infancy. A Tour of the World in Photochromes is at the Swiss Camera Museum, Vevey, until 21 August. Here: Street food in the Strada del Porto in Naples, Italy, 1899. (Photo by Swiss Camera Museum/The Guardian)

An Iranian soldier guards two German tourists near the Iranian-Turkish border during World War II. Since the British occupation of Iran, all Axis nationals are being expelled from the country. (Photo by Three Lions/Getty Images). Circa 1941

An Egyptian security guard screams at people as medics bring in a stretcher to carry the wounded after the attack which killed President Anwar Sadat, October 6, 1981, as he watched a military parade. (Photo by AP Photo)

Trainers from Tianjiao Special Guard/Security Consultant Ltd. Co. engage trainees dressed in swimming suits as they crawl on the beach during a training session in Sanya, Hainan province January 8, 2012. (Photo by CHINA DAILY/Reuters)

A humanoid robot named Kansei, meaning “sensibility” in Japanese, makes a facial expression depicting “happiness”, next to the word “Love” during a demonstration at a laboratory of Meiji University's Robot and Science Institute in Kawasaki, south of Tokyo in this June 4, 2007 file photo. Three-fourths of robot installations over the next decade are expected to be concentrated in four areas: transportation equipment, including the automotive sector; computer and electronic products; electrical equipment and machinery. Labor costs have climbed in countries such as China that have been popular for outsourcing production, while technological advances for robots allow them to be more flexible and perform more tasks. (Photo by Yuriko Nakao/Reuters)

“«The Red Detachment of Women» (simplified Chinese: 红色娘子军) is a Chinese ballet which premiered in 1964. It is perhaps best known in the West as the ballet performed for U.S. President Richard Nixon on his visit to China in February 1972. Adapted from the earlier film of the same title under the personal direction of Zhou Enlai, which in turn adapted from the novel by Liang Xin, it depicts the liberation of a peasant girl in Hainan Island and her rise in the Chinese Communist Party”.

Masks of Republican presidential candidate Donald Trump (C) and Joaquin "El Chapo" Guzman (2nd L) are seen at Grupo Rev in the Mexican city of Cuernavaca near Mexico City, October 14, 2015. (Photo by Henry Romero/Reuters)

Ford is celebrating the 50th anniversary of the Mustang with a limited-edition model and a display atop the Empire State Building. The car had to be broken into five pieces for the ride up the building’s elevators and reassembled late at night, when the deck is closed to visitors. Photo: The 2015 Ford Mustang convertible, assembled overnight, sits on the observation deck of the Empire State Building. (Photo by Hiroko Masuike/The New York Times)