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)

People run as Haiti's Senator Jean Marie Ralph Fethiere (PHTK) fires a gun in the air, injuring Chery Dieu-Nalio, a photographer for Associated Press, while facing opposition supporters in the parking lot of the Haitian Parliament and Senate, as the government attempted to confirm the appointment of nominated Prime Minister Fritz William Michel, in Port-au-Prince, Haiti on September 23, 2019. (Photo by Andres Martinez Casares/Reuters)

A bomb-laden Su-25 jet at the Hmeimim air base in December 2015. Russia's lease agreement obliged Assad’s military to safeguard the perimeter of the Hmeimim base, while giving Moscow legal jurisdiction over the facilities inside. Negotiating perimeter protection from Syria’s new rulers will be vital for the Russian bases in an era of wire-controlled drones immune to jamming. (Photo by AP Photo)

Sikhs wield swords during their clash inside the complex of the holy Sikh shrine, the Golden Temple, in Amritsar June 6, 2014. Sikhs wielding swords clashed inside the compound of their religion's holiest shrine on Friday, the 30th anniversary of a controversial raid by security forces that flushed out separatist militants holed up in the temple. REUTERS/Munish Sharma

People stand under a giant Czech flag as they arrive to light candles at the base of a statue of St. Wenceslas to commemorate the death of former Czech President Vaclav Havel on December 18, 2011 in Prague, Czech Republic. Havel, who led the Velvet Revolution that forced communist rule in Czechoslovakia to crumble in 1989, died in the early morning today in his sleep at the age of 75. (Photo by Sean Gallup/Getty Images)

The zombies, cowgirls, and witches were out in force Saturday night on Clematis Street as thousands of people came to Moonfest to celebrate Halloween. They came from Broward County, Boynton Beach, Wellington, Port St. Lucie, and as far away as Germany and Sweden. Photo: Joe Smith, 60, Boca Raton. (Photo by Thomas Cordy/The Palm Beach Post)

A woman places her fingers into the crucifix-shaped holes in one of the ancient columns in the Church of the Nativity on December 22, 2011 in Bethlehem, West Bank. (Photo by Uriel Sinai/Getty Images)

“Maeklong Railway Market, located in Samut Songkhram, Thailand, around 37 miles west of Bangkok, looks like any other open-air market in Asia. HOWEVER...”. – Kaushik via Amusing Planet. Photo: Maeklong Railway Market (Photo by Trent Strohm)