Brain-on-a-chip. Dazzling in green and magenta this image shows the nerve fibres (in green) produced by neural stem cells (in magenta) as they grow on a synthetic gel. Captured by a technique known as confocal microscopy, the image is part of research shedding light on how tinkering with the environment can affect the way in which nerve fibres grow. (Photo by Collin Edington and Iris Lee/Massachusetts Institute of Technology/Wellcome 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 schoolgirl stands next to the Kenya-Uganda railway line during the partial reopening of schools, after the government scrapped plans to cancel the academic year due to the coronavirus disease (COVID-19) pandemic, in Kibera slums of Nairobi, Kenya on October 12, 2020. (Photo by Thomas Mukoya/Reuters)

U.S. Secretary of State John Kerry stands inside the historic Shackleton hut near McMurdo Station, Antarctica, Friday, November 11, 2016. Kerry became the highest-ranking American official to visit Antarctica when he landed for a two-day trip on Friday. He's been hearing from scientists about the impact of climate change on the frozen continent. Kerry's aides described the trip as a learning opportunity for the secretary of state. He has been receiving briefings from scientists working to understand the effects of climate change on Antarctica. Kerry has made climate change an intensive focus of American diplomacy during his term, and had previously spent decades working on the issue as a U.S. senator. Trump has called climate change a hoax and said he would “cancel” U.S. involvement in the landmark Paris Agreement on global warming. (Photo by Mark Ralston/Pool Photo via AP Photo)

A Hindu holy man, or sadhu, smeared with ashes smokes marijuana in a chillum during the Shivaratri festival on the premises of Pashupatinath Temple in Kathmandu, Nepal, March 7, 2016. Hindu holy men from Nepal and India come to this temple to take part in the Maha Shivaratri festival. Celebrated by Hindu devotees all over the world, Shivaratri is dedicated to Lord Shiva, and holy men mark the occasion by praying, smoking marijuana or smearing their bodies with ashes. (Photo by Navesh Chitrakar/Reuters)

A hand of a devotee is pictured as she rings a bell while offering prayers to the chariot of God Bhairab during the Bisket festival in Bhaktapur, Nepal, April 13, 2016. During the festival, also regarded as Nepalese New Year, images of the Hindu god Bhairava and his female counterpart Bhadrakali are enshrined in two large chariots and pulled to an open square after which rituals and festivities are performed. (Photo by Navesh Chitrakar/Reuters)

A man walks behind camels at the Birqash Camel Market, ahead of Eid al-Adha or Festival of Sacrifice, on the outskirts of Cairo September 29, 2014. Birqash Camel Market, one of the biggest markets for camel meat in Africa, draws sellers from Libya, Sudan, Somalia and other regions in Egypt. The camels sold at the market are also used in tourism. Traders say that the selling rate for a camel in 2014 is anywhere between 5,000 and 20,000 Egyptian pounds (700 – 2800 USD). (Photo by Amr Abdallah Dalsh/Reuters)

A hot air balloon floats past an almost full rising moon on a warm fall evening near Encinitas, California October 5, 2014. (Photo by Mike Blake/Reuters)