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)

Two workers shovel mud from the river as they look for gold on March 25, 2014 in Lampang, Thailand. Thai villagers from Wang Nuea, North of Thailand, look for gold in the river every year during the drought season. They are able to make an average around USD 15 per day, however two years ago they reached USD 200 in one day due to the river level dropping so much. The workers begin to search for gold at 10 AM and work until sunset, often working second jobs in the day in order to survive. (Photo by Borja Sanchez-Trillo/Getty Images)

A nurse helps an injured bomb victim sitting at the back of a pickup truck at the Asokoro General Hospital in Abuja, April 14, 2014. A morning rush-hour bomb killed at least 35 people at a Nigerian bus station near the capital on Monday, raising concerns about the spread of an Islamist insurgency after the first such attack on Abuja for two years. Suspicion fell on Boko Haram, though there was no immediate claim of responsibility from the Islamist group mainly active in the northeast. Five hours after the blast, officials had given no death toll. Reuters journalists counted at least 35 bodies. (Photo by Afolabi Sotunde/Reuters)

A wheelbarrow loaded with two butchered pigs is seen at La Saline slaughterhouse in Port-au-Prince, Haiti, March 19, 2015. Reuters photographer Andres Martinez Casares: “The grunts of a pig or the bleating of a goat are one thing. Then there's the sound of animals about to be killed. That's something else. If you haven't heard that before, it's quite something... (Photo by Andres Martinez Casares/Reuters)

A groundskeeper uses a bamboo broom at Kasumigaike Pond at Kenrokuen Garden in Kanazawa, Japan on January 12, 2016. The japanese garden, located next to Kanazawa Castle, encompasses over 28 acres in downtown Kanazawa. With two ponds, rolling hills with streams and bridges, is considered a strolling-style landscape garden. It's regarded as one of the top three most beautiful gardens in Japan. (Photo by Linda Davidson/The Washington Post)

A man passes by an unfinished street art graffiti made in a stairway by French street artists Zag and Sia in Paris on March 1, 2016. The two artists drew inspiration from famous “Liberty Leading the People” (La Liberte guidant le peuple) painting by French Eugene Delacroix commemorating the July Revolution of 1830 and viewed as a symbol of the French Republic. (Photo by Joel Saget/AFP Photo)

A vendor decorates a sacrificial camel ahead of the Eid al-Adha festival, in Karachi, Pakistan, 23 August 2016. Eid al-Adha is the holiest of the two Muslims holidays celebrated each year, with this year will be celebrated on 02nd September. Eid al-Adha marks the yearly Muslim pilgrimage (Hajj) to visit Mecca, the holiest place in Islam. Muslims slaughter a sacrificial animal and split the meat into three parts, one for the family, one for friends and relatives, and one for the poor and needy. (Photo by Rehan Khan/EPA)

Two female revelers engage in a beer drinking contest in the Hacker Pschorr tent on the first day of the 2017 Oktoberfest beer fest on September 16, 2017 in Munich, Germany. Oktoberfest is the world's largest beer celebration and typically draws over six million visitors over its three-week run. Oktoberfest includes massive beer tents, each run by a different Bavarian brewer, as well as amusement rides and activities. (Photo by Philipp Guelland/Getty Images)