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)

Yann Arthus-Bertrand (born March 13, 1946 in Paris) is a French photographer, journalist, reporter and environmentalist.

Darren Julien poses with two of Princess Diana's dresses which will be auctioned through WE tv & Wedding Central at Julien's Auctions in Beverly Hills on May 7th in celebration of the Royal Wedding, with a portion of the proceeds going to charity are shown at Times Square on April 20, 2011 in New York City. (Photo by Slaven Vlasic/Getty Images)

Afghan police officers secure a transportation headquarters that was besieged for two days last weekend, on May 14, 2011 in Kandahar, Afghanistan. Taliban gunmen and suicide bombers unleashed a major assault May 7, 2011 on locations in Kandahar that included the governor's compound, the mayor's office, police stations, and an intelligence agency headquarters. (Photo by Majid Saeedi/Getty Images)

A woman sits next to a Gollum figure on the “Middle-earth Shuttle” subway train November 18, 2003 in New York City. The train's cars were decorated with Middle-earth creatures, vines, moss and stones to celebrate the November 18 DVD and VHS release of the Special Extended Edition of The Lord of the Rings: The Two Towers. (Photo by Mario Tama/Getty Images)

Two rare ceramic heads from a series by Japanese ceramicist Takahiro Kondo are displayed at the “Masterpiece London” Auction on June 29, 2011 in London, England. The second “Masterpieces London” sale is currently underway at The Royal Hospital Chelsea, showcasing fine and decorative arts, jewellery, classic cars, fine wines and sculpture from over 30 dealers. The event takes place from June 30 – July 5, 2011. (Photo by Dan Kitwood/Getty Images)

Volunteers receive a professional massage from qualified therapists as they break a world record for the largest ever simultaneous massage during Massage en Masse at Lavandula Lavender Farm on March 30, 2010 in Daylesford, Australia. Two hundred and sixty three massage therapists each massaged a volunteer, breaking the former world record of 167, set in 2009 in Washington DC. (Photo by Scott Barbour/Getty Images)

Members of the English Defence League (EDL) take part in a demonstration through the streets of Leicester on February 4, 2012 in Leicester, England. Up to two thousand members of the EDL gathered in the centre of Leicester as an opposing demonstration by anti-fascists held their protest nearby. (Photo by Christopher Furlong/Getty Images)