Ivorian police officers of the Anti-Riot Brigade (BAE) contain the crowd during a performance by French rapper Okou Armand Gnakouri known as Kaaris during the Festival of Urban Music of Anoumabo (Femua) in Abidjan on April 28, 2019. The performance of French-Ivorian rapper Kaaris at the Festival of Urban Music of Anoumabo (Femua) in Abidjan escalated into violence after a crowd surge, causing some minor injuries, according to an AFP journalist at the concert. (Photo by Sia Kambou/AFP Photo)

Traffic lights feature illustrations of a homosexual couple in downtown Frankfurt Main, Germany, 18 July 2019. An annual gay pride parade will take place on 20 July 2019 in Frankfurt to commemorate Christopher Street Day (CSD). The event commemorates the riots that erupted following a police raid in 1969 at a gay bar on Christopher Street in Greenwich Village, New York City. (Photo by Armando Babani/EPA/EFE)

Former Soviet President Mikhail Gorbachev and his daughter Irina Virganskaya attend the Free Your Mind Award Presentation at the Cinema For Peace charity dinner at the China Club on November 8, 2009 in Berlin, Germany. (Photo by Sean Gallup/Getty Images). BERLIN – NOVEMBER 08 2009

Challenger Deep Submersible is shown for the first time at the Virgin Group Media Announcement by the President & CEO of Virgin Airlines Sir Richard Branson at the Newport Harbor Yacht Club on April 5, 2011 in Balboa, California. (Photo by John M. Heller/Getty Images)

王梓鈺 (王梓钰) – 音阙诗听 – 惊蛰【24节气系列歌曲】. Wang Ziyu is a female singer from Mainland China and a member of the music club Yinqueshi Listening. Representative works include “Jingzhe”.

Riot police face off with demonstrators at the “Occupy Denver” camp on October 29, 2011 in Denver, Colorado. Following a march by protesters, police moved in on their encampment to tear down recently erected tents. They arrested numerous protesters, pepper-sprayed others and others reportedly fired rubber bullets at the crowd during the confrontation. (Photo by John Moore/Getty Images)

Musician Kirk Hammett of Metallica performs onstage during The Big 4 held at the Empire Polo Club on April 23, 2011 in Indio, California.