A homeless man rests on the side of a street at the old quarter of Yemen's capital Sanaa November 27, 2015. (Photo by Khaled Abdullah/Reuters)

A woman tries to cross a flooded street as people walk on a trestle bridge during high water, in Venice, northern Italy, Friday, November 15, 2019. Exceptionally high tidal waters returned to Venice on Friday, prompting the mayor to close the iconic St. Mark’s Square and call for donations to repair the Italian lagoon city just three days after it experienced its worst flooding in 50 years. (Photo by Andrea Merola/ANSA via AP Photo)

7 year old Soni has a basket of coal lifted onto her head by her mother, 28 year old Savita, after having scavenged coal illegally from an open-cast coal mine in the village of Bokapahari on February 08, 2012 near to Jharia, India. (Photo by Daniel Berehulak /Getty Images)

A boy stands at the door of a 60-year-old cable car in the town of Chiatura, some 220 km (136 miles) northwest of Tbilisi, September 12, 2013. (Photo by David Mdzinarishvili/Reuters)

Mr. Zhong Hua, of Johns Hopkins University School of Medicine, took this image of the peripheral nerves (those outside of the brain) in an 11.5-day-old mouse embryo, magnified five times. (Photo by Zhong Hua)

A four-month-old snow fox cub named “Vesna” (“Spring”) leaps next to a Zoo employee at the Royev Ruchey Zoo in Krasnoyarsk, Russia, on August 6, 2013. (Photo by Ilya Naymushin/Reuters)

Mulan Jamilah, a 6-year-old Bengal tiger, kisses caretaker Abdullah Sholeh, 33, in the garden beside their home on January 20, 2014 in Malang, Indonesia.