Jason Garcia poses as The Joker from Batman at the 2015 Comic-Con International in San Diego, California, July 9, 2015. (Photo by Sandy Huffaker/Reuters)

A couple embraces at the San Fermin festival in Pamplona, northern Spain, July 10, 2016. (Photo by Eloy Alonso/Reuters)

Attendees dressed as Poison Ivy and Harley Quinn arrive for opening day of the annual Comic-Con International in San Diego, California, United States July 21, 2016. (Photo by Mike Blake/Reuters)

An unidentified runner gestures while being attended by medical services following the first running of the bulls of the San Fermin festival in Pamplona, northern Spain, July 7, 2015. Two runners were gored in the run that lasted 2 minutes and 23 seconds, according to local media. (Photo by Eloy Alonso/Reuters)

Convention goers dressed as bright colored Wookiees, a fictional species from the US epic space opera franchise Star Wars, prepare for a group photo outside the Comic Con 2016 in San Diego, California, USA, 22 July 2016. The San Diego Comic Con 2016 runs from 21 until 24 July. (Photo by David Maung/EPA)

A police officer detains a woman on suspicion of collaborating with the 18th street gang during a "Safe House" operation at the Concepcion neighbourhood in San Salvador, July 2, 2015. Salvadoran police make “Safe House” operations at dangerous neighbourhoods of the capital to prevent murders, according to local media. (Photo by Jose Cabezas/Reuters)

A visitor looks at a creation by Russian artist Irina Nakhova presented at the Russia's pavilion during the 56th International Art Exhibition (Biennale d'Arte) titled “All the Worlds Futures” on May 5, 2015 in Venice. (Photo by Gabriel Bouys/AFP Photo)

People cool off in a fountain outside the Southbank Centre on June 30, 2015 in London, England. The UK is currently experiencing a heatwave, with temperatures of 35 degree celsius forecast tomorrow in some parts of the country. The extreme heat has already seen train cancellations and a health warning has been issued. (Photo by Rob Stothard/Getty Images)