In this May 14, 2016 photo, children wearing their school backpacks climb on a cliff using a bamboo ladder on their way home from school in Zhaojue county, southwest China's Sichuan province. A village in China's mountainous west where schoolchildren must climb an 800-meter (2,625-foot)-high bamboo ladder secured to a sheer cliff face may get a set of steel stairs to improve it's safety. (Photo by Chinatopix via AP Photo)

In this combination image visitors to the London Super Comic Convention dress as their favourite Marvel comic characters at ExCel on February 25, 2012 in London, England. Visitors to the Comic Convention are encouraged to wear a costume of their favourite character. (Photo by Peter Macdiarmid/Getty Images)

“San Diego Comic-Con International, also known as Comic-Con International: San Diego (as given on its website), and commonly known as Comic-Con or the San Diego Comic-Con, was founded as the Golden State Comic Book Convention and later the San Diego Comic Book Convention in 1970 by Shel Dorf and a group of San Diegans. It is traditionally a four-day event (Thursday through Sunday — though a three-hour preview night on Wednesday is open to professionals, exhibitors, and some guests pre-registered for all four days) held during the summer in San Diego, California, United States, at the San Diego Convention Center. Comic-Con is both the name of the annual event and the common name of the organization”. – Wikipedia

Photo: Rannie Rodil and Laya Bella attend Day 1 at Comic-Con 2011 on July 21, 2011 in San Diego, California. (Photo by John Shearer/Getty Images)

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)

Attendees arrive dressed as their favourite comic characters for the MCM London Comic Con, a convention to celebrate the culture of comic books and related art forms, in London, Britain, May 25, 2018. (Photo by Toby Melville/Reuters)

Tao Xiangli gets out of his homemade submarine after operating it in a lake on the outskirts of Beijing September 3, 2009. Amateur inventor Tao, 34, made a fully functional submarine, which has a periscope, depth control tanks, electric motors, manometer, and two propellers, from old oil barrels and tools which he bought at a second-hand market. He took 2 years to invent and test the submarine which costs 30,000 yuan ($4,385). (Photo by Christina Hu/Reuters)

Labourers who work nearby nap on a road as cars drive past in Chongqing Municipality, July 23, 2013. (Photo by Reuters/Stringer)

Passengers wait for a train to depart from the Hankou Railway Station in Wuhan, central China's Hubei province, Friday January 13, 2017. Officials expect that Chinese travelers will make almost 3 billion trips during the holiday travel rush that starts runs through Feb. 21. These trips include intercity flights, trains and local bus rides to villages for China's 1.4 billion people. (Photo by Chinatopix via AP Photo)