A man dressed as a Santa Claus poses at the front of the Kollhoff Tower at Potsdamer Platz square in Berlin December 14, 2014. (Photo by Hannibal Hanschke/Reuters)
NFL player Rob Gronkowski, of the New England Patriots, from second left, accepts the best comeback athlete award with his brothers, NFL free agent Chris Gronkowski and former NFL player Dan Gronkowski at the ESPY Awards at the Microsoft Theater on Wednesday, July 15, 2015, in Los Angeles. (Photo by Chris Pizzello/Invision/AP Photo)
Dancers perform during the opening ceremony before the Russia 2018 World Cup Group A football match between Russia and Saudi Arabia at the Luzhniki Stadium in Moscow on June 14, 2018. (Photo by Sergei Bobylev/TASS via Getty Images)
The northern lights, or aurora borealis, appear in the sky over the Bamburgh lighthouse at Stag Rock in Northumberland, England on September 28, 2016. (Photo by Owen Humphreys/PA Wire via ZUMA Press)
A group of Japanese schoolgirls marching in formation during a school visit to the third regiment to experience the soldier's way of life. (Photo by Fox Photos/Getty Images). Circa 1938
Mercedes driver Nico Rosberg, right, of Germany steers his car in front of Mercedes driver Mercedes driver Lewis Hamilton of Britain, center and Ferrari driver Sebastian Vettel of Germany during the Austrian Formula One Grand Prix race at the Red Bull Ring in Spielberg, southern Austria, Sunday, June 21, 2015. (AP Photo/Kerstin Joensson)
The sirens Charybdis and Scylla resided in the Sicilian Sea. Homer tells us that because Charybdis had stolen the oxen of Hercules, Zeus struck her with a thunderbolt and changed her into a whirlpool whose vortex swallowed up ships. In Charybdis the circular movement of water inside a transparent acrylic cylinder forms an air-core vortex in the centre. Steps wrap around the cylinder and allow spectators to view the vortex from above. The cylinder was manufactured in Grand Junction, Colorado.
Aleksandra Krunic, of Serbia, drops to the court after defeating Petra Kvitova, of the Czech Republic, during the third round of the 2014 U.S. Open tennis tournament, Saturday, August 30, 2014, in New York. (Photo by Kathy Willens/AP Photo)