The second and final qualification motor (QM-2) test for the Space Launch System's booster, June 28, 2016, at Orbital ATK Propulsion Systems test facilities in Promontory, Utah. During the Space Launch System flight the boosters will provide more than 75 percent of the thrust needed to escape the gravitational pull of the Earth, the first step on NASA's Journey to Mars. (Photo by Bill Ingalls/NASA)

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)

A woman is having a massage at the Lukacs Bath in Budapest, Hungary June 28, 2016. Hungary's capital owes its popularity as a tourist destination partly to its numerous hot springs and bathing culture which have drawn visitors to the area since Roman times. Bath houses range from large, ornate 19th-century buildings like the Gellert and the Szechenyi to tiny Ottoman Turkish-era hamams, some of them more than 500 years old. (Photo by Bernadett Szabo/Reuters)

An Afghan girl carries water on her back as she climbs a hill in Kabul, Afghanistan February 20, 2017. A growing population is straining water supplies in Afghanistan's capital, forcing those who can afford it to dig unregulated wells ever deeper to tap a falling water table. Finding water in arid Afghanistan is virtually always a challenge, but a drop in the groundwater level in Kabul caused by overuse and drought is making it even more difficult for residents, especially the poor. (Photo by Omar Sobhani/Reuters)

In this Sunday, March 12, 2017, picture a Don Sphinx cat reaches for a judge while being evaluated, in Bucharest, Romania. More than 1,500 dogs and 150 cats from twelve countries were evaluated during a three day pet show and competition in the Romanian capital. (Photo by Vadim Ghirda/AP Photo)

Women with their faces painted as various Hindu deities take part in a celebration a day after the first democratic constitution was announced in Kathmandu, Nepal September 21, 2015. Nepal adopted its first full democratic constitution on Sunday, a historic step for a nation that has witnessed war, a palace massacre and devastating earthquakes since a campaign to create a modern state began more than 65 years ago. (Photo by Navesh Chitrakar/Reuters)

Photographer Brian Finke spent nearly two years traversing the friendly skies, following the life of flight attendants in the air and on the ground, from Delta and Hawaiian Air, to Hooters Air, Southwest, Air France, British Airways, Air Asia, and dozens more. His images of flight attendants waving, applying makeup and deboarding plans while smiling appear as if they were ripped from an advertisement in a glossy magazine. Here: Tiger Airways, Singapore, 2006. (Photo by Brian Finke/The Washington Post)

Carlos Martinez (L), a representative of the Guinness World Records, examines the cooking process of a chocolate coin during an attempt to break the Guinness World Record for the biggest chocolate coin in Caracas, Venezuela, October 1, 2015. More than 80 people will work with 100% Venezuelan cacao to create the coin that is estimated to weigh 1,000 kg, according to local media. (Photo by Carlos Garcia Rawlins/Reuters)