Joshua Patino stands on a ladder to put finishing touches on a giant dinosaur exhibit at PAX East in the Boston Convention and Expo Center, Thursday, April 21, 2016, in Boston. PAX East, an annual celebration of gaming culture, is expected to draw tens of thousands of visitors Friday through Sunday. It's a place where serious gamers can preview unreleased video games and devices, compete in tournaments, hear live music and meet others for whom gaming is a way of life. (Photo by Elise Amendola/AP Photo)

A policeman kick in the door of a residence next to the Black Panther headquarters in New Orleans as they moved in following a shootout, September 15, 1970. Other heavily armed policemen stand at ready. (Photo by Jack Thornell/AP Photo)

Eight-year-old Niu Dongfang trains at the No. 2 Beijing Shuangqiao School January 13, 2005 in Beijing, China. Most of students in the gymnastics school have to study more than five years from as young as age six before they become athletes. (Photo by Guang Niu/Getty Images)

Catherine, Duchess of Cambridge speaks to soldiers as she arrives at Calgary Airport on July 7, 2011 in Calgary, Canada. (Photo by Chris Jackson/Getty Images)

The hot air balloon “Hopper T Frog” from Park City, Utah, peeks over the red rock cliffs during the 23nd Annual Red Rock Balloon Rally at Red Rock State Park December 6, 2003 near Gallup, New Mexico. (Photo By Douglas Tesner/Getty Images)

Members of the Palestinian Hamas security forces show their skills as they take part in a graduation ceremony in Gaza City on January 22, 2017. (Photo by Mahmud Hams/AFP Photo)

A boy bursts a soap-bubble at Gorky Park in Moscow on July 19, 2017. (Photo by Mladen Antonov/AFP Photo)

Dancers perform on stage during Diwali celebrations in Leicester, Britain November 11, 2015. (Photo by Darren Staples/Reuters)