A vendor prepares paan, a betel nut-based chewable stimulant at a flower market in Kolkata, India, January 18, 2016. (Photo by Rupak De Chowdhuri/Reuters)

View at one of the sculptures by Swiss artist H.R. Giger during the opening of the Ars Electronica 2013 exhibition “HR Giger. The Art of Biomechanics” in Linz, Austria, 04 September 2013. (Photo by EPA/RUBRA)

In this artist's impression supplied by the ESO (European Southern Observatory) on April 25, 2007, the planetary system around the red dwarf, Gliese 581, is pictured showing what astronomers believe is the most earth like planet found outside our solar system to date. Using the ESO 3.6-m telescope in Chile, astronomers have uncovered the planet which could have water running on its surface. The planet orbits the faint star Gliese 581, which is 20.5 light-years away in the constellation Libra. (Photo by ESO via Getty Images)

Members of the Russian Red Army Choir perform at Water Front Theatre in Beirut September 13, 2014. (Photo by Jamal Saidi/Reuters)

Police officers stand near a fishing boat, the Carolina Queen III, as it rests in shallow water just off Rockaway Beach, Thursday, February 25, 2016, in the Queens borough of New York. Authorities say a Coast Guard vessel overturned while assisting the fishing boat that ran aground in an inlet off New York City. (Photo by Frank Franklin II/AP Photo)

An injured NATO soldier lies on the ground following a suicide car bomb attack that targeted foreign military vehicles in the Afghan capital Kabul on June 30,2015. A powerful blast hit downtown Kabul on June 30 as a suicide car bomber targeted foreign military vehicles, officials said, with casualties feared. The blast came on the main road to the airport, around 500 meters (550 yards) from the US embassy and near a base for foreign troops.“It was a suicide car bomber targeting a convoy of foreign forces in Kabul”, interior ministry spokesman Sediq Sediq said. (Photo by Wakil Kohsar/AFP Photo)

Girls of University of Cincinnati Stage Grecian Games on April 29, 1921. Garbed in costumes of ancient Greece, fair students of the University of Cincinnati, Ohio arranged a set of Grecian Games for the benefit of the University athletic fund. All of the girl students of the University, who take a great interest in outdoor games and athletics, took part in the games. The fund was greatly increased through the staging of the unique attraction and the girls purpose to give a return engagement. The accompanying photographs show the girl contestants in their Grecian costumes. Photo shows the start of the 100 yard dash. (Photo by Bettmann Archive/Getty Images)

Graduates dance as they take part in a “Last school bell” ceremony at a school in Minsk, Belarus on May 30, 2018. (Photo by Vasily Fedosenko/Reuters)