Royal tour India
Prince William signs the visitors' book at the India Gate war memorial as his wife looks onManish Swarup/AFP

When Prince William and Kate Middleton visit Bhutan, they may encounter the Himalayan kingdom's most unusual tradition: giant penis murals. Phallic symbols are everywhere in Bhutan, particularly in rural areas. Ten-foot-tall graphic images are painted on the walls of homes. Giant carved wooden erections adorn the entrances to temples, while smaller ones hang from the eaves of houses and dangle from the rear-view mirrors in cars.

Some of the paintings and carvings are very explicit and detailed. It is believed they aid in fertility, ward off evil spirits and dispel malicious gossip.

The use of phallic symbols can be traced back to a Tibetan Buddhist monk named Drukpa Kunley (1455–1529), popularly known as the Mad Saint or Divine Madman. He was based at the Chimi Lhakhang monastery near Punakha, the former capital of Bhutan. Kunley used sexual intercourse, alcohol and dirty poetry to spread Buddhist teachings.

He was known for using his penis to spread enlightenment. His unusual methods of teaching earned him the title The Saint of 5,000 Women. Kunley's penis was called the Thunderbolt of Flaming Wisdom, as it could unnerve and subdue demonesses. He is also reported to have lectured entire villages, using farts to illustrate the concept of impermanence.

IBTimes UK presents a gallery of Bhutan's phallic murals (they may be spiritual, but they're also probably NSFW).

Bhutan penis murals
A man looks out of a window next to a giant penis mural in ThimpuDesmond Boylan/Reuters
Bhutan penis murals
A child sits on a doorstep flanked by penis murals in Kabesa villageSingye Wangchuk/Reuters
Bhutan penis murals
A woman talks to a customer at her shop, decorated with a penis mural, in Kabesa villageAdnan Abidi/Reuters
Bhutan penis murals
A phallic symbol is seen on a house in the Punakha valleyDesmond Boylan/Reuters
Bhutan penis murals
Children play near a large penis mural on a house in ParoDesmond Boylan/Reuters
Bhutan penis murals
A man walks past phallus symbols painted on the wall of his house in the village of Tshephu in the Punakha valleyDesmond Boylan/Reuters
Bhutan penis murals
Penises and deer are painted on a house in Sopsokha village, PunakhaiStock
Bhutan penis murals
Phalluses, flowers and deer are painted on the facade of a building in Sopsokha villageiStock
Bhutan penis murals
Large penis drawings are seen on a house in BhutaniStock
Bhutan penis murals
People sit in front of a house adorned with penis paintings in Nagang VillageiStock
Bhutan penis murals
Phallus symbols are painted on a shop in Sopsokha village, PunakhaiStock
Bhutan penis murals
Tshewang Nidup poses in front of his house, adorned with phallus drawings, on the outskirts of ThimphuManan Vatsyayana/AFP
Bhutan penis murals
Big phallus murals are seen on a home near BumthangiStock
Bhutan penis murals
A stylised phallus and dragon decoration is seen on a house in ThimpuDesmond Boylan/Reuters

Prince William and Kate Middleton will head to the Himalayan kingdom of Bhutan on 14 April, at the invitation of King Jigme Khesar Namgyel Wangchuck and Queen Jetsun Pema. Bhutan's royal couple – often dubbed the Wills and Kate of the Orient – married in October 2011, around six months after the British royal wedding. The young royal couple had a son in February 2016. After a traditional Bhutanese welcome ceremony, the royal couples will have dinner at Lingkana Palace in the capital, Thimphu.

The Duke and Duchess of Cambridge will hike for around six hours to reach Paro Taktsang monastery, also known as the Tiger's Nest. The monastery was built in the 17th century on the side of a cliff, around a cave that was the focal point for Guru Padmasambhava, who is credited for introducing Buddhism to Bhutan.