A security exercise takes place along the River Thames on January 19, 2012 in London, England. The exercise including around 44 police officers, 94 military personnel, 15 boats and a Royal Navy Lynx helicopter was conducted by both the Metropolitan Police and the Royal Marines and designed to test their joint capability ahead of the 2012 London Olympic Games. (Photo by Dan Kitwood/Getty Images)

U.S. Democratic presidential candidate Hillary Clinton takes a photo with supporters John Nelson, 32, (L) and Dan Stifler, 32, (C) after speaking at the UFCW Union Local 324 in Buena Park, California, U.S. May 25, 2016. (Photo by Lucy Nicholson/Reuters)

A man hugs a child at the Santuario de Nuestra Senora de Guadalupe during a celebration on the Virgin of Guadalupe Day in Guatemala City, December 12, 2015. According to Catholic believers, December 12 marks the anniversary of the apparition of the Virgin of Guadalupe at the Cerro del Tepeyac in Mexico. (Photo by Jorge Dan Lopez/Reuters)

A Sumatran Tiger looks at visiting children from it's enclosure during the ZSL London Zoo's annual stocktake of animals on January 5, 2015 in London, England. The zoo's annual stocktake requires keepers to check on the numbers of every one of the 800 different animal species, including every invertebrate, bird, fish, mammal, reptile, and amphibian. (Photo by Dan Kitwood/Getty Images)

A worker settles mud in a mold to make bricks at a brick factory in Tixtla, on the outskirts of Chilpancingo, in the Guerrero state, January 26, 2015. The worker earns a salary of 15 Mexican pesos, or one dollar, for every 100 bricks made on a working day of at least 5 hours. (Photo by Jorge Dan Lopez/Reuters)

One of three Sperm Whales, which were found washed ashore near Skegness over the weekend, lays on a beach on January 25, 2016 in Skegness, England. The whales are thought to have been from the same pod as another animal that was found on Hunstanton beach in Norfolk on Friday. (Photo by Dan Kitwood/Getty Images)

NFL player Rob Gronkowski, of the New England Patriots, from second left, accepts the best comeback athlete award with his brothers, NFL free agent Chris Gronkowski and former NFL player Dan Gronkowski at the ESPY Awards at the Microsoft Theater on Wednesday, July 15, 2015, in Los Angeles. (Photo by Chris Pizzello/Invision/AP Photo)

Charlotte Caslick of Australia is tackled by Jasmine Joyce of Wales during the Rugby Sevens Women's Pool B match between Australia and Wales on day nine of the Gold Coast 2018 Commonwealth Games at Robina Stadium on April 13, 2018 on the Gold Coast, Australia. (Photo by Dan Mullan/Getty Images)