Young couples compete in Rock' n'Roll & Co, an all- Russian acrobatic rock' n'roll competition in Kazan, Russia on November 4, 2017. Acrobatic rock’n’roll is a discipline for couples combining energetic dancing with acrobatic moves. (Photo by Yegor Aleyev/TASS via Getty Images)

Ukrainians jump over a fire in Kiev, Ukraine, 06 July 2017, as they celebrate the traditional pagan holiday of Ivana Kupala. Ivana Kupala is celebrated, during the summer solstice, on the shortest night of the year, marking the beginning of summer and is celebrated in Ukraine, Belarus, Poland and Russia on the night of 06 July. People sing and dance around bonfires, play games and perform traditional rituals. Young people jump over bonfires in order to test their bravery. Couples holding hands jump over the flames to test their love. If the couple does not succeed it is predicted to split up. Traditionally, children and young unmarried women wear wreaths of wild flowers on their heads to symbolize purity. (Photo by Sergey Dolzhenko/EPA)

Brides and grooms sit on top of an Indonesian Army vehicle during a mass wedding ceremony organized in Jakarta, Indonesia, Wednesday, January 28, 2015. More than 5000 couples participated on a mass wedding ceremony to legalized the previous religious marriage ceremonies. Most of the couples have not officially registered their marriage for economic reasons as it cost up to 500,000 IDR (35 euro) to legalized a marriage. The ceremony organized by Rajawali Foundation. (Photo by Achmad Ibrahim/AP Photo)

Indian brides and grooms wait for the start of a mass wedding in New Delhi on June 15, 2014. Some 92 low-income and disabled couples tied the knot in a free mass wedding ceremony organised by the non-profit organisation Narayan Sewa Sansthan. (Photo by Chandan Khanna/AFP Photo)

A couple looks at their flooded street from behind their home's window in La Plata, in Argentina's Buenos Aires province, where at least 35 people were killed by flooding overnight, on April 3, 2013. (Photo by Natacha Pisarenko/Associated Press)

China has recently relaxed its one child policy that was used to control a burgeoning population. A couple has their wedding photo taken in an old quarter of Beijing on May 24, 2016. (Photo by Michael Robinson Chavez/The Washington Post)

This is the moment a dog who had his legs cut off as a punishment, is able to walk again thanks to prosthetic limbs, and being rescued by John and Gill Dalley, a couple who moved to Phuket, Thailand, from Leeds to set up the Soi Dog Foundation, August 1, 2016. (Photo by Caters News Agency)

A couple takes a photo outside the MUJA (Jurassic Museum of Asturias) in Colunga, northern Spain, November 6, 2015. The scientific team of the Jurassic Museum of Asturias (MUJA) presents their latest studies on the fossil of a Ichthyosaur, which acccording to them is the most complete found in the Iberian Peninsula and one of the few in the world. (Photo by Eloy Alonso/Reuters)