Mr. Zhong Hua, of Johns Hopkins University School of Medicine, took this image of the peripheral nerves (those outside of the brain) in an 11.5-day-old mouse embryo, magnified five times. (Photo by Zhong Hua)

A commuter exits a closed off station after a subway train derailment, Tuesday, June 27, 2017, in the Harlem neighborhood of New York. A subway train derailed near a station in Harlem on Tuesday, frightening passengers and resulting in a power outage as people were evacuated from trains along the subway line. The Fire Department of New York said a handful of people were treated for minor injuries at around 10 a.m. It said there was smoke but no fire. Delays were reported throughout the subway system. (Photo by Mary Altaffer/AP Photo)

A bear that wandered into a University of Colorado Boulder dorm complex falls from a tree after being tranquilized by Colorado wildlife officials on April 26, 2012. Colorado wildlife official Jennifer Churchill said that the 200-pound male bear was tagged and relocated to a remote Rocky Mountain area. The bear was hit by two cars on May 3 and died. (Photo by Andy Duann)

A large balloon of a face of “ojisan”, a middle aged man, floats in the sky above the grounds of Nishiki elementary school in Utsunomiya in Tochigi prefecture, 100km north of Tokyo on December 21, 2014. Members of art group “Me”, meaning “eye” in Japanese and the Utsunomiya Museum of Art launched an art installation “The Day an Ojisan's Face Floated in the Sky”, a 15-meter by 10-meter face balloon of the depicted man, who was auditioned in the city, looking down on his home town from the sky. (Photo by Yoshikazu Tsuno/AFP Photo)

People walk by a car destroyed by a tree which fell during a storm and strong winds, in Limoges, on May 21, 2014. High winds upto 120 km/h and storms have caused at least one death and cut off some 42 000 homes from electricity today in the Midi-Pyrenees region of France. (Photo by Pascal Lachenaud/AFP Photo)

Members of the Russian Red Army Choir perform at Water Front Theatre in Beirut September 13, 2014. (Photo by Jamal Saidi/Reuters)

Civilians, who fled the violence in Manbij city, arrive to the southeastern rural area of Manbij, in Aleppo Governorate, Syria June 19, 2016. (Photo by Rodi Said/Reuters)

A Hindu priest waits to perform prayers next to Tejas, India's first locally-built Light Combat Aircraft (LCA), before its induction into the Indian Air Force at the Hindustan Aeronautics Limited (HAL) Airport in Bengaluru, India, July 1, 2016. (Photo by Abhishek N. Chinnappa/Reuters)