The NASA Extreme Environment Mission Operations (NEEMO) 21 mission began on July 21 as an international crew of aquanauts splashed down to the undersea Aquarius Reef Base, located 62 feet below the surface of the Atlantic Ocean in the Florida Keys National Marine Sanctuary. The NEEMO 21 crew will perform research both inside and outside the habitat during a 16-day simulated space mission. During simulated spacewalks carried out underwater, they will evaluate tools and mission operation techniques that could be used in future space missions, including journeys to Mars. (Photo by Karl Shreeves/NASA)

A Tenggerese shaman praying for worshippers at Widodaren cave during the Tenggerese Hindu Yadnya Kasada festival on July 31, 2015 in Probolinggo, East Java, Indonesia. The festival is the main festival of the Tenggerese people and lasts about a month. On the fourteenth day, the Tenggerese make the journey to Mount Bromo to make offerings of rice, fruits, vegetables, flowers and livestock to the mountain gods by throwing them into the volcano's caldera. The origin of the festival lies in the 15th century when a princess named Roro Anteng started the principality of Tengger with her husband Joko Seger, and the childless couple asked the mountain Gods for help in bearing children. The legend says the Gods granted them 24 children but on the provision that the 25th must be tossed into the volcano in sacrifice. The 25th child, Kesuma, was finally sacrificed in this way after initial refusal, and the tradition of throwing sacrifices into the caldera to appease the mountain Gods continues today. (Photo by Ulet Ifansasti/Getty Images)

The November 2018 Square Print Sale, presented by Magnum Photos and Aperture, brings together over 100 images to explore perspectives on transition and transformation in photography. Here: New York City, 1965, by Joel Meyerowitz. “A girl on a Vespa on her way to who knows where, when the light stopped her at the 72nd street crossing near the Dakota, where John Lennon would one day cross paths with his fate. She takes this moment to finesse a fingernail before she resumes her downtown journey, while I, stopping at the same crossing, but on foot, leap into the street to capture this vision of a dream girl before time takes her on her way”. (Photo by Joel Meyerowitz/Courtesy Aperture)

Stormtrooper Jacob French is pictured on day 5 of his over 4,000 kilometre journey from Perth to Sydney approximately 25 kilometres from Mandurah on July 15, 2011 in Perth, Australia. French aims to walk 35-40 kilometres a day, 5 days a week, in full Stormtrooper costume until he reaches Sydney. French is walking to raise money for the Starlight Foundation - an organisation that aims to brighten the lives of ill and hostpitalised children in Australia. (Photo by Paul Kane/Getty Images)

A busy rush hour sees thousands of commuters climbing on board a train – as well as holding onto its sides and sitting on the roof before it speeds off. Men, women and children climb and are pulled up onto the roof of the train, which is around 12ft (3.6m) high, as they try to find themselves a space. With no seats available inside, many commuters decide to take the risk and choose a rooftop view for their journey out of Dhaka city, in Bangladesh. (Photo by Yousuf Tushar/Solent News & Photo Agency)

A Tibetan mastiff dog is displayed for sale at a mastiff show in Baoding, Hebei province, south of Beijing on March 9, 2013. Fetching prices up to around 750,000 USD, mastiffs have become a prized status-symbol amongst China's wealthy, with rich buyers across the country sending prices skyrocketing. Owners say the mastiffs, descendents of dogs used for hunting by nomadic tribes in central Asia and Tibet are fiercely loyal and protective. Breeders still travel to the Himalayan plateau to collect young puppies, although many are unable to adjust to the low altitudes and die during the journey. (Photo by Ed Jones/AFP Photo)

Discovered in 1952 by French bio-speleologist Henri Coiffait, the waterfall and accompanying sinkhole were fully mapped in the 1980s by the Spéléo club du Liban. The cave is also known as the "Cave of the Three Bridges." Traveling from Laklouk to Tannourine one passes the village of Balaa, and the "Three Bridges Chasm" (in French "Gouffre des Trois Ponts") is a five-minute journey into the valley below where one sees three natural bridges, rising one above the other and overhanging a chasm descending into Mount Lebanon. During the spring melt, a 90–100-metre (300–330 ft) cascade falls behind the three bridges and then down into the 250-metre (820 ft) chasm. A 1988 fluorescent dye test demonstrated that the water emerged at the spring of Dalleh in Mgharet al-Ghaouaghir.