In a picture taken with an underwater camera, a couple stands in front of a Polynesian priest during their underwater wedding ceremony on October 25, 2014 in Bora-Bora, in French Polynesia. The ceremony lasts twenty minutes and costs around 2700 euros. (Photo by Ben Thouard/AFP Photo)

Pakistani brides attend a mass marriage ceremony in Karachi late March 26, 2013. Some 110 couples participated in the mass wedding ceremony organised by a local charity welfare trust Al Ghousia. (Photo by Asif Hassan/AFP Photo)

Woman on swings attached to a float during the Sexual Freedom Parade, part of Naughty in N'awlins held in New Orleans, Louisiana, Wednesday July 5th, 2017. These are the photos from inside the world’s largest swinging convention for couples. The exclusive images reveal the unlikely couples who like to engage in sexual relations with other people besides their partners – and show that swinging is more ‘normal’ than you think. (Photo by Mathew Growcoot/News Dog Media)

A couple takes a selfie as Hoa Binh hydroelectric power plant opens the flood gates after a heavy rainfall caused by Talas typhoon in Hoa Binh province, outside Hanoi, Vietnam July 20, 2017. (Photo by Reuters/Kham)

Brides display their hands decorated with henna around a bride as she poses for her own photographer during a mass marriage ceremony in which, according to its organizers, 70 Muslim couples took their wedding vows, in Ahmedabad, India, February 11, 2018. (Photo by Amit Dave/Reuters)

Passengers travel in an overcrowded train in the eastern Indian city of Patna, February 23, 2010. (Photo by Krishna Murari Kishan/Reuters)

In Mumbai, the windows of new high-rise apartment blocks, old low-rise residential buildings and shantytown shacks portray the disparity in living conditions and incomes in the Indian city. Rents for a place to live range from more than $2,000 to less than $5 a month. Here: Windows and doors of an old residential building are pictured in central Mumbai October 10, 2014. The cost for buying a residential apartment in Mumbai close to the city centre ranges from 12,000 Indian rupees ($ 200) per square feet to 112,552 Indian rupees ($ 1800) per square feet. (Photo by Danish Siddiqui/Reuters)

A newly-married couple takes a nap before their mass wedding ceremony at the CheongShim Peace World Center in Gapyeong, South Korea, Sunday, February 17, 2013. Some 3,500 South Korean and foreign couples exchanged or reaffirmed marriage vows in the Unification Church's mass wedding arranged by Hak Ja Han Moon, a wife of the late Rev. Sun Myung Moon, the controversial founder of the Unification Church. (Photo by Lee Jin-man/AP Photo)