A bunker at aformer Swiss artillery fortress called Heldsberg stands near the town of St. Margareten, Switzerland March 22, 2015. Heldsberg fortress, located on the Swiss-Austrian border near the River Rhine and Lake Constance was built from 1938 to 1940 and remained in military use until 1992. Since 1993 it is open to the public as Fortress Museum Heldsberg. (Photo by Arnd Wiegmann/Reuters)

A supporter of the Houthis has a poster attached to his waist of Iranian Major-General Qassem Soleimani, head of the elite Quds Force, who was killed in an air strike at Baghdad airport, during a rally to denounce the U.S. killing, in Saada, Yemen January 6, 2020. The writing on the poster reads: “God is the Greatest, Death to America, Death to Israel, Curse on the Jews, Victory to Islam”. (Photo by Naif Rahma/Reuters)

Police and the Russian National Guard (Rosgvardia) servicemen patrol Red Square in front of the Spasskaya tower of the Kremlin in Moscow on October 24, 2022, as part of security reinforcement measures. (Photo by Alexander Nemenov/AFP Photo)

Igor, a 40 year-old Ukranian soldier embraces his wife in front of his military basement in the center of Odessa on March 17, 2022. Odessa, which Ukraine fears could be the next target of Russia's offensive in the south, is the country's main port and is vital for its economy. But the city of one million people close to the Romanian and Moldovan borders also holds a special place in the Russian imagination. (Photo by Bulent Kilic/AFP Photo)

In this November 28, 1966 file photo, one of the 10 beagles involved in the first test of the Veterans Administration Hospital in East Orange, N.J. smokes a cigarette through a machine linked to its windpipe by a plastic tube to test any link between smoking and emphysema. (Photo by AP Photo)

Soap Bubble Structures by Kym Cox. Bubbles optimise space and minimise their surface area for a given volume of air. This phenomenon makes them a useful tool in many areas of research, in particular, materials science and “packing” – how things fit together. Bubble walls drain under gravity, thin at the top, thick at the bottom, which interferes with travelling lightwaves to create bands of colour. Black spots show the wall is too thin for interference colours, indicating the bubble is about to burst. (Photo by Kym Cox/2019 Science Photographer of the Year/RPS)

A lightning strikes through smoke from fuel storage tanks that exploded near Cuba's supertanker port in Matanzas, Cuba on August 8, 2022. (Photo by Alexandre Meneghini/Reuters)

People dressed in fifties-style outfits dance during the 23rd Rockin' Race Jamboree International Festival in downtown Torremolinos, near Malaga, southern Spain February 4, 2017. (Photo by Jon Nazca/Reuters)