National Guardsmen are put through riot training in Boston's Commonwealth Armory on Friday, October 18, 1974. Massachusetts Gov. Francis W. Sargent called up the guard to quell school violence, but the city has been relatively calm and the guard has remained in the armories. (Photo by JWG/AP Photo)

An aerial view taken with a drone shows the autumnally colored Fuerst-Pueckler-Park near Cottbus, eastern Germany, Saturday, October 29, 2016. The park, composed with great sensitivity in the 19th century by Prince Hermann von Pueckler-Muskau, is considered as one of the last great German landscape gardens. (Photo by Patrick Pleul/DPA via AP Photo)

A couple walk in the Retiro park in Madrid on November 17, 2020 as a thick fog falls on the Spanish capital. (Photo by Gabriel Bouys/AFP Photo)

Irene Bowker, 88 years old at the Punk Rebellion festival at The Winter Gardens, talks to a woman with a tatooed head and mohican haircut in Blackpool, Lancashire, UK on August 6, 2015. A clash cultures at the famous seaside town of Blackpool as punks attending the annual Rebellion festival at the Winter Gardens come shoulder to shoulder with traditional holidaymakers. (Photo by MediaWorldImages/Alamy Stock Photo)

Ke$ha performs live on stage during the second day of the Wireless Festival at Hyde Park on July 2, 2011 in London, England. (Photo by Jim Dyson/Getty Images)

People look at a tanker after it fell into a caved-in area on a road in Xi'an, Shaanxi province, July 27, 2013. No casualty was reported in the accident, according to local media. (Photo by Reuters/Stringer)

More than 6 billion people live in countries where serious levels of public sector corruption are fueling inequality and exploitation, according to Transparency International's 2015 index of perceived public sector corruption. The group's annual report measures perceptions of corruption due to the secrecy surrounding most corrupt dealings. Two thirds of the 168 countries assessed were identified as having a serious corruption problem. Somalia, which has been mired in conflict since civil war broke out in 1991, ranks bottom of the list. (Photo by Feisal Omar/Reuters)

A woman carries a stone cross in a cemetery in the village of Copaciu, southern Romania, on May 2, 2013. As part of a Holy Week tradition, Romanians visit, on Maundy Thursday, the graves of their loved ones, light fires and share food with community members in memory of the departed. Orthodox worshipers celebrate Easter on May 5. (Photo by Andreea Alexandru/ Mediafax)