A mother prays for success for her child in the college entrance examinations at a Buddhist temple in Seoul, South Korea, November 12, 2015. About 630,000 students on Thursday sat for the annual exams that could lead them to one of the country's top universities. In South Korea, there is no higher achievement than to be accepted by a prestigious university. As a result, many students prepare for these entrance exams from an early age, often studying up to 16 hours a day for years to take this test. (Photo by Kim Hong-Ji/Reuters)

Number 10. BELL H-13 SIOUX was a two-bladed, single engine, light helicopter built by Bell Helicopter. Westland Aircraft manufactured the Sioux under license for the British military as the Sioux AH.1 and HT. In 1947, the United States Air Force ordered the improved Bell Model 47A. Most were designated YR-13 and three winterized versions were designated YR-13A. The United States Army first ordered Bell 47s in 1948 under the designation H-13. These would later receive the name Sioux. The Bell-built H-13 B is seen airborne in this April 29, 1951 photo. The helicopter is equipped with a 173 horsepower engine, cruises at 85 miles per hour, climbs 900 feet in a minute and has a service ceiling of 11,500 feet. (Photo by AP Photo)

Intrigued by photographing time, Singapore-based photographer Fong Qi Wei created single, composite pictures from a sequence of images spanning 2-4 hours. He concentrated on capturing sunrises and sunsets as they evolved over different landscapes, seascapes, and cityscapes. He then digitally stitched the images together to get a snapshot of time passing over the scene for his series “Time is a Dimension”. “Most paintings and photographs are an instance of time”, Wei explained in his artist’s statement. “That’s not the way the world works. We experience a sequence of time, and that’s why a video is somehow more compelling than a freeze frame”. (Photo by Fong Qi Wei/Thoughtful Photography)

Shot by Bert Hardy, the black and white images show prisoners carrying out remedial tasks such as untying knots in post office string and sewing mail bags. Other intriguing shots show lags doing their daily one hour outdoor exercise, being frisked for contraband items by officers during a routine “rub down” and serving evening meals. Strangeways was designed by Alfred Waterhouse and cost £170,000 ($207,910) to build. The prison, famed for its prominent ventilation tower and imposing design, has become a local landmark. Here: A prison officer frisking prisoners during the “rub-down” at Strangeways Prison in Manchester, UK on November 1948. (Photo by Bert Hardy/Picture Post/Hulton Archive/Getty Images)

The Malabar Giant squirrel – double the size of their grey relatives and measuring up to 36 inches (91.5 cm) from head to tail – lives deep in the forests of India. The athletic animals can leap an incredible 20 feet (6 m) between trees. Photographer Kaushik Vijayan, 39, snapped the animals in their native habit to produce these stunning images. Kaushik, from Kerala State, India, said: “Up until that point I had never heard about a squirrel like that or seen one. The sight was an absolute feast for my eyes. The squirrels fascinated me and I got excited to capture this beauty on my camera”. (Photo by Kaushik Vijayan/South West News Service)

“NASA's Pathfinder, Pathfinder Plus, Centurion and Helios Prototype were an evolutionary series of solar- and fuel-cell-system-powered unmanned aerial vehicles. AeroVironment, Inc. developed the vehicles under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. They were built to develop the technologies that would allow long-term, high-altitude aircraft to serve as “atmospheric satellites”, to perform atmospheric research tasks as well as serve as communications platforms”. – Wikipedia

Photo: The solar-electric Helios Prototype flying wing is flies over the Hawaiian islands of Niihau and Lehua during the first solar-powered test flight July 14, 2001 from the U.S. Navy's Pacific Missile Range Facility on Kauai, HI. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later in the summer. (Photo Courtesy of NASA/Getty Images)

“Car2go fleet is located throughout the greater downtown area and can be accessed on-demand or booked 24 hours in advance. The members may use the vehicle for as long as they like, without committing to a specific return time or return location”. – Wikipedia

Photo: A car2go employee shows how members can use a smartphone or iPad app to locate and reservec car2go vehicles March 22, 2012 in Washington, DC. Beginning March 24, car2go will offer the first free-floating car-sharing service in Washington and Portland, Oregon, where customers can use the smartphone app within the 34-square-mile “Home Area”. After paying a one-time $35 membership fee, drivers can then rent the Smart Fortwo vehicles by the minute, paying only for the time they use the vehicle, with discounted rates for hourly and daily use. (Photo by Chip Somodevilla/Getty Images)

In this Monday, April 27, 2015 photo, a Nepalese man walks over fallen rocks and past a crushed car on the way to Dhunche, Nepal, a village in Langtang National Park, two days after a 7.8-magnatude earthquake hit the region. The photographer, Joe Sieder, said the man was part of a group of Nepalese workers and trekkers who left Syabrubesi earlier that day and hiked about 30 km (19 miles) for 13 hours, mostly over boulder-strewn roads with some small landslides along the way to make their way to a passable road. (Photo by Joe Sieder via AP Photo)