Tourists pose with pigeons in the flooded St. Mark's Square in Venice, on November 7, 2014. The high water, a combination of high tides and a strong Scirocco wind in the Adriatic Sea, stood at 110 centimeters early on November 7. The city has for years been wrestling with the problems posed by the threat of rising sea levels. (Photo by Olivier Morin/AFP Photo)

A singer drinks from a huge bowl of beer on-stage as he pays tribute to the customers after performing at an entertainment club in Beijing, on May 8, 2014. (Photo by Jason Lee/Reuters)

Costumed revellers walk in the streets of Lucerne during the annual carnival parade on Rose Monday March 3, 2014. (Photo by Sigi Tischler/AP Photo/Keystone)

In this Wednesday, July 23, 2014 file photo, Omaha photographer Lane Hickenbottom photographs the night sky in a pasture near Callaway, Neb. With no moon in the sky, the Milky Way was visible to the naked eye. More than one-third of the world’s population can no longer see the Milky Way because of man-made lights, according to a scientific paper by Light Pollution Science and Technology Institute's Fabio Falchi and his team members, published on Friday, June 10, 2016. (Photo by Travis Heying/The Wichita Eagle via AP Photo)

Two traditional folk dancers performing in Teheran, Iran. (Photo by Keystone Features/Getty Images). 25th January 1961

Students from St Andrews University are covered in foam as they take part in the traditional Raisin Weekend in the Lower College Lawn, at St Andrews in Scotland on October 22, 2018. The “raisin weekend” stems from a gift of raisins (now flour and foam) traditionally given by a first year student to their academic “parents” in gratitude for their guidance. (Photo by Russell Cheyne/Reuters)

Pitch invader Kinsey Wolanski is taken away by security during the Champions League final soccer match between Tottenham Hotspur and Liverpool at the Wanda Metropolitano Stadium in Madrid, Saturday, June 1, 2019. (Photo by Toby Melville/Reuters)

Dancers are warming up backstage during the Tango Dancing Tournament at the XIII International Tango Festival in Medellin, Colombia, on June 18, 2019. The Tango Festival takes place between the 16th and 24th of June. (Photo by Joaquin Sarmiento/AFP Photo)