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)

Kenichi Ito runs on his arms and legs on a race course on his way to setting the Guinness World Record fastest time for the 100-meter dash on all fours at Komazawa Olympic Park Stadium in Tokyo Thursday, November 14, 2013. The 30-year-old Japanese finished in 16.87 seconds Thursday, shaving more than half a second off his 2012 run of 17.47. (Photo by Shizuo Kambayashi/AP Photo)

Olive Ridley turtle hatchlings (Lepidochelys olivacea) sit in baskets and trays at the turtle camp La Gloria, before their release into the ocean in Tomatlan November 15, 2013. Twenty years ago, Mexico's government implemented ecological plans to protect the sea turtles from being hunted for their leather and meat and established conservation areas and a pay system for local residents to protect turtle nests. Millions of baby turtles hatch on the shores in November and December, according to an environmental group. It is estimated that in 2012, there were 20 million newborns. Hatching season is still underway, but officials say they expect there will be even more turtles born this year. (Photo by Alejandro Acosta/Reuters)

Female indigenous players vie for the ball during the final match of Peladao, the amateur football tournament, in Manaus, Amazonas state, Brazil, on November 24, 2013. Peladao is known as the biggest amateur football tournament in the world, with more than 1000 teams competing in various categories since 1973. The indigenous category was created in 2005 and eight teams participated this year. (Photo by Yasuyoshi Chiba/AFP Photo)

Nine year old girl Barsati reacts while walking on a tightrope in Mumbai on February 11, 2014. Barsati, and her younger brother Rajababu, (4) earn an average of around 2000 rupees (32 dollars) per day from pedestrians and tourists performing various acts on the tightrope near the city's iconic landmark Gateway of India. (Photo by Indranil Mukherjee/AFP Photo)

A meteor streaks over the sky during the Perseid meteor shower at the Maculje archaeological site near Novi Travnik August 12, 2014. According to NASA, the annual Perseid meteor shower reaches its peak on August 12 and 13 in Europe. The fireballs from the meteorites are fast and plentiful, although a nearly full moon (Supermoon) makes it difficult to view them this year, the agency adds. (Photo by Dado Ruvic/Reuters)

Man prepares wigs as he waits for customers in downtown Johannesburg, on August 5, 2014. Some estimates put Africa's dry hair industry at as much as $6 billion a year; Nigerian singer Muma Gee recently boasted that she spends 500,000 naira ($3,100) on a single hair piece made of 11 sets of human hair. (Photo by Siphiwe Sibeko/Reuters)

Model, skydiver and wing-suit jumper Roberta Mancino, 33, swims with a whale shark on February 2014 in Isla Mujeres, Mexico. A female skydiver swims with whale sharks, manta rays and sailfish – the fastest fish in the sea. Model, skydiver and wing-suit jumper Roberta Mancino, 33, jumped from a boat into the ocean surrounding Isla Mujeres near the northern Peninsula of Mexico. The incredible project involved two trips to the stormy winter seas – one in February 2013 and one a year later in February 2014. (Photo by Shawn Heinrichs/Barcroft Media)