A fighter jet flies above as Ukrainian soldiers sit on an armoured personnel carrier in Kramatorsk, in eastern Ukraine April 16, 2014. Ukrainian government forces and separatist pro-Russian militia staged rival shows of force in eastern Ukraine on Wednesday amid escalating rhetoric on the eve of crucial four-power talks in Geneva on the former Soviet country's future. (Photo by Marko Djurica/Reuters)

Londoners walking through Potters Field Park were surprised to see a “money tree” blooming with £9820 in £10 notes, the average amount a working British family has in savings, on July 24, 2014 in London, England. The tree was planted by Sunlife to encourage the nation to start saving at least £10 a month for a brighter future. (Photo by Tristan Fewings/Getty Images for SunLife)

People walk throw the Damascus gate during the Jerusalem Festival of Lights on June 15, 2011 at Jerusalem's Old City, Israel. The festival opened on Wednesday night and will run for a week in the Old City of Jerusalem, hosting Israeli and international artists and creators who will display their installations throughout the week. (Photo by Uriel Sinai/Getty Images)

Yak near Yamdrok lake, Tibet. It is a long-haired bovinae found throughout the Himalayan region of south Central Asia, the Tibetan Plateau and as far north as Mongolia and Russia. The Tibetan economy is dominated by subsistence agriculture. Due to limited arable land, the primary occupation of the Tibetan Plateau is raising livestock, such as sheep, cattle, goats, camels, yaks, dzo, and horses. The Tibetan yak is an integral part of Tibetan life. (Photo by Dennis Jarvis)

A commuter exits a closed off station after a subway train derailment, Tuesday, June 27, 2017, in the Harlem neighborhood of New York. A subway train derailed near a station in Harlem on Tuesday, frightening passengers and resulting in a power outage as people were evacuated from trains along the subway line. The Fire Department of New York said a handful of people were treated for minor injuries at around 10 a.m. It said there was smoke but no fire. Delays were reported throughout the subway system. (Photo by Mary Altaffer/AP Photo)

Carolaine Reis and her son Miguel Alves, residents of the Aglomerado da Serra favela, wear a protective mask against the spread of the new Coronavirus (COVID-19) made by the seamstresses of the Remexe Favelinha studio, in the Aglomerado da Serra favela, on April 13, 2020 in Belo Horizonte, Brazil. Facial masks follow the protocol and guidelines defined by the Ministry of Health. Around 6,000 masks have already been produced. The masks are being distributed to a part of the population and sold throughout the country, in the amount of 5 reais per unit. (Photo by Pedro Vilela/Getty Images)