Children exercise before a wrestling practice session at an old Basque ball game gymnasium in downtown Havana, October 30, 2014. (Photo by Alexandre Meneghini/Reuters)

A boy jumps over a puddle of water on the outskirts of Havana, Cuba March 21, 2016. (Photo by Ueslei Marcelino/Reuters)

A Ukrainian serviceman fires a 2S7 Pion self-propelled gun during military exercises near the village of Divychky in Kiev region, Ukraine, October 21, 2016. (Photo by Valentyn Ogirenko/Reuters)

A camel is seen as he is being brought for the foot surgery at the Dubai Camel Hospital in Dubai, UAE, December 11, 2017. (Photo by Satish Kumar/Reuters)

Female members of the Chinese People's Liberation Army (PLA) honour guard stand behind a string to ensure that they are in a straight line before a welcoming ceremony for Russian President Vladimir Putin outside the Great Hall of the People in Beijing, China, June 25, 2016. (Photo by Kim Kyung-Hoon/Reuters)

Visitors hold ice blocks to cool themselves in hot weather at a water park on June 23, 2016 in Chongqing, China. Citizens and visitors escaped high temperature at a water park in Yangren Jie (also known as Foreigner Street), Nan'an District of south China's Chongqing. (Photo by VCG/VCG via Getty Images)

The Enemy, 1944. With the outbreak of world war two, photojournalism was enlisted in defence of Mother Russia. In this photo by Anatoli Egorov, who was wounded in action, corporal Stepan Vasiljevich Ovcharenko shoots at enemy troops with a machine gun. (Photo by Anatoli Egorov/Lumiere Brothers Center for Photography)

A street in the Cuban capital, Havana, is home to 12 sets of twins, ranging from toddlers to senior citizens. Some say it could be something in the water. Others point to a tree with mystical significance for locals. And maybe it's just chance. Photo: In this September 29, 2013 photo, nine-year-old twin sisters Camila, left, and Carla Rodriguez pose for a portrait along their street in Havana, Cuba. 12 sets of twins live along two consecutive blocks in western Havana, ranging in age from newborns to senior citizens. “We love living on this block because we have twin friends”, said Carla. (Photo by Ramon Espinosa/AP Photo)