People in Kathmandu joke that the face mask has now become part of the national dress – an indispensable accessory in an effort to protect themselves from the dust. Nepal has the worst air quality in the world, according to the Environmental Performance Index. (Photo by Pete Pattisson/The Guardian)

“A small British company with a dream of building a re-usable space plane has won an important endorsement from the European Space Agency (ESA) after completing key tests on its novel engine technology. Reaction Engines Ltd believes its Sabre engine, which would operate like a jet engine in the atmosphere and a rocket in space, could displace rockets for space access and transform air travel by bringing any destination on Earth to no more than four hours away”. – Chris Wickham via Reuters. Photo: Artist's impression of Skylon. (Photo by Reaction Engines Ltd)

Freshmen take part in a military training at Chongqing City Vocational College on September 23, 2021 in Chongqing, China. (Photo by Chen Shichuan/VCG via Getty Images)

Most people know Nikon as a purveyor of pro and consumer-grade digital cameras. But the company's expertise with optics bleeds over into related markets – it's one of the science community's major suppliers of microscopes. And each year the company asks the community to send it some of their favorite images of tiny objects. A panel of scientists and journalists have chosen the best of this past year's submissions, which Nikon has placed on its Small World site.

Photo: Honorable Mention. “Snow crystal, illuminated with colored lights (5x)”. (Photo by Dr. Kenneth Libbrecht, California Institute of Technology (Caltech), Department of Physics, Pasadena, California, USA)

A worker stands under the Airlander 10 hybrid airship during its unveiling in Cardington, Britain March 21, 2016. The world's largest aircraft has been unveiled for the first time since being fully assembled in the UK. The 302ft (92m) long Airlander 10 – part plane, part airship – was floated in a First World War hangar in Bedfordshire. (Photo by Darren Staples/Reuters)

The Dinagyang is a religious and cultural festival in Iloilo City, Philippines held on the fourth Sunday of January, or right after the Sinulog In Cebu and the Ati-Atihan in Aklan. It is held both to honor the Santo Niño and to celebrate the arrival on Panay of Malay settlers and the subsequent selling of the island to them by the Atis. wiki

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)

Princess Charlene poses after the arrival of the Riviera Water Bike Challenge in support of the Princess Charlene of Monaco Foundation, in Nice, France, June 4, 2017. (Photo by Eric Gaillard/Reuters)