A photographer tested the concentration of several pairs of dogs as he captured their reactions to treat time in a series of shots. Christian Vieler, 47, of Waltrop, Germany, has been a professional dog photographer since 2016. He came up with the idea of snapping two dogs catching treats simultaneously. Here: Basset Hounds. (Photo by Vieler Photography/Caters News Agency)

A Southwest Airlines jet takes off from Reagan National Airport with a thunderhead to the east on June 20, 2017 in Alexandria, VA. (Photo by Jonathan Newton/The Washington Post)

A participant wearing Kokoshnik, the Russian traditional headwear, walks out of the water during winter swimming festival in the town of Podolsk, south of Moscow, Russia January 5, 2017. (Photo by Maxim Shemetov/Reuters)

Passengers prepare to take part in the No Pants Subway Ride in Prague, Czech Republic, Sunday, January 8, 2017. The No Pants Subway Ride began in 2002 in New York as a stunt and has taken place in cities around the world since then. (Photo by Petr David Josek/AP Photo)

Aide Choque, wearing a mask amid the COVID-19 pandemic, jumps with her skateboard during a youth talent show in La Paz, Bolivia, Wednesday, September 30, 2020. Young women called “Skates Imillas”, using the Aymara word for girl Imilla, use traditional Indigenous clothing as a statement of pride of their Indigenous culture while playing riding their skateboards. (Photo by Juan Karita/AP Photo)

A reflection on waste liquid shows a tourist walking near the Blue mosque at the Sultanahmet Square on the first day of the Muslim fasting month of Ramadan in Istanbul on April 13, 2021. (Photo by Ozan Kose/AFP Photo)

Aerial photo taken on June 19, 2021 shows the scenery of Mount Huashan in northwest China's Shaanxi Province. (Photo by Xinhua News Agency/Rex Features/Shutterstock)

A diver in a pool at the Army 2021 International Military and Technical Forum, at the Patriot military park in Moscow Region, Russia on August 22, 2021. (Photo by Sergei Karpukhin/TASS/Alamy Live News)