An Amur tiger walks across a passageway after a news conference at the Philadelphia Zoo, Wednesday, May 7, 2014, in Philadelphia. The see-through mesh pathway called Big Cat Crossing is part of a national trend called animal rotation that zoos use to enrich the experience of both creatures and guests. (Photo by Matt Slocum/AP Photo)

Revelers throw a woman to the air during the opening and the firing of the “Chupinazo” rocket which starts the 2014 Festival of the San Fermin Running of the Bulls on July 6, 2014 in Pamplona, Spain. The annual Fiesta de San Fermin, made famous by the 1926 novel of US writer Ernest Hemmingway entitled “The Sun Also Rises”, involves the daily running of the bulls through the historic heart of Pamplona to the bull ring. (Photo by Pablo Blazquez Dominguez/Getty Images)

An employee feeds a one-week-old coati cub with a bottle of milk at the Royev Ruchey zoo in the suburbs of Krasnoyarsk, Siberia, October 10, 2014. The mother of three cubs refused to nurse them, according to zoo employees. (Photo by Ilya Naymushin/Reuters)

A competitor shouts as he takes part in the “Tough Guy” adventure race near Wolverhampton, central England, on January 29, 2017. The Tough Guy event, which is being held for the final time in its 30th year, challenges thousands of competitors to run a gruelling course whilst negotiating over 200 obstacles including: water, fire, and tunnels. (Photo by Oli Scarff/AFP Photo)

Italian Air Force's aerobatic demonstration team, the Frecce Tricolori leave colourful vapour trails as they fly over the Altare della Patria monument on Republic Day (Festa della Repubblica) in Rome, Italy, 02 Jun 2017. The anniversary marks the founding of the Italian Republic in 1946. (Photo by Massimo Percossi/EPA)

This photo take on December 16, 2016 shows macaques monkeys playing on a motorbike in the grounds of a temple in Jaipur in the Indian state of Rajasthan. (Photo by Dominique Faget/AFP Photo)

An inmate (L) tends to a fellow prisoner while performing ear candling during an alternative therapy session as part of the ACUDA programme, at a complex of ten prisons in Porto Velho, Rondonia State, Brazil, August 27, 2015. Ear candling, which involves inserting a hollow cone-shaped device into the ear canal and lighting the exposed end, is believed by practitioners to draw out earwax. According to ACUDA the therapy is beneficial for the inmates' emotional health. (Photo by Nacho Doce/Reuters)

These images show the unique bond a group of free divers formed with gigantic sperm whales. Swimming just inches away from the huge mammals, the divers are dwarfed in size, made to look like specks in comparison. The photos were taken by renowned underwater photographers Alexandre Roubaud and Alexandre Voyer, who are based in Paris but travel the world to capture such stunning imagery. Here: a diver with a sperm whales. (Photo by Alexandre Roubaud/Alexandre Voyer/Caters News)