A schoolgirl collects rubbish from Karachi's Clifton beach early morning April 22, 2013, during a cleaning campaign as part of the commemoration of Earth Day. (Photo by Akhtar Soomro/Reuters)

Participants hold red scarves as they celebrate the “Chupinazo” marking the start at noon sharp of the San Fermin Festival at Castle square in Pamplona, northern Spain on July 6, 2013. Ten of thousands of people packed Pamplona's streets for a drunken kick-off to Spain's best-known fiesta: the nine-day San Fermin bull-running festival. (Photo by Pedro Armestre/AFP Photo)

A model walks the runway wearing creations by Bianca Spender during Mercedes-Benz Fashion Week Australia in Sydney, Australia, 14 May 2018. (Photo by Dan Himbrechts/EPA/EFE)

A palomino horse's mane is seen against the sky at Spancil Hill horse fair in Spancil Hill, Ireland June 23, 2018. (Photo by Clodagh Kilcoyne/Reuters)

Aerial view of a boat working in the green water of Taihu Lake covered by blue-green algae, Wuxi city, Jiangsu province, China on May 23, 2018. (Photo by Imaginechina/Rex Features/Shutterstock)

The northern lights, or aurora borealis, illuminate the sky over Flakstad beach on Lofoten Islands in the Arctic Circle on September 5, 2017. (Photo by Jonathan Nackstrand/AFP Photo)

Ivanka Trump poses with Kristina Hilko, Lauren Shovlin, and Anna Nesbitt, members of the Girls of Steel Robotics initiative, at the Astrobotic Technology facility in Pittsburgh, Pennsylvania on August 14, 2018. (Photo by Jason Cohn/Reuters)

Winners of a competition enjoy a meal 450ft up on the roof of a central London skyscraper on August 21, 2018, as Deliveroo recreates “Lunch Atop a Skyscraper”, the photograph taken during the construction of the Rockefeller Center in New York City, 1932. (Photo by Jonathan Brady/PA Images via Getty Images)