In pictures: the world's most unusual ancient rituals

Renowned photojournalist Jeremy Hunter has spent 35 years travelling the world, photographing the most fascinating and obscure ancient rituals. His archive, Let's Celebrate 365, holds more than 10,000 photographs, each one a glimpse into the richest cultures and communities on the planet. From unusual Easter celebrations in Guatemala to the world's largest Muslim gathering, here are 10 of his most interesting insights:

Great Head-Washing Festival (Mahamastakabhisheka), Shravanabelagola, India

This festival has been taking place since 981 AD when the giant 17m-high monolithic statue of Bahubali was commissioned. Bahubali (whose name means "arm strength") is a much-revered deity among Jains. They believe he lived around 20,000 years ago and that, during his time, he challenged his brother Bharat to a fight to determine who would reign Supreme over the Kingdom of Abhanatha. His enormous arm strength meant he was close to killing his sibling – he was mortified by what he had done, so he discarded all his clothes as a penance, pulled out his hair and stood naked and motionless for a year.

The festival celebrates this event with the statue being “washed” for ten days by around two million devotees. “Washing” is considered so auspicious that, in 2006, a prominent Jain bid $1.3 million dollars to be the first to “wash” Bahubali.

When is it? The festival is usually celebrated every 12 years. It was last held in 2006, so it should next take place in 2018.

Living Ghosts (Egungun), Dakon village, Benin

Living Ghosts (Egungun) are all members of a highly secret organisation. They represent the souls of the dead who have returned to Earth to pass on specific advice to the living. It is believed that their word is final, as it is a direct word of the gods.

When is it? Egungun usually visit villages north of Ouidah in Benin during January and February. A local "fixer" should be able to determine the specific village where they can be found.

Biswa Ijtema, River Turag at Tongi, Bangladesh

This is the largest gathering of Muslims in the world. During just one day Biswa Ijtema attracts 5 million devotees, twice the number that journey annually to the Hajj in Mecca. Bangladesh is a tiny country (the size of Ireland), yet it has the population of Russia. Ninety percent of this population is Muslim, most with a very low per-capita income. This annual “coming-together” is an opportunity for Muslims to seek the divine blessings of Allah without the steep cost of travelling to Saudi Arabia.

When is it? Biswa Ijtema is celebrated every January.

Great Monlam Festival, Labuleng Monastery, East Tibet

Established in 1709, the Labuleng Monastery is considered to be the leading Tibetan monastery town outside Lhasa. It is the centre of the Yellow Hat sect of Tibetan Buddhism, followers of the Dalai Lama. During this four-day festival, the entire monkhood attend the Great Debate in the presence of the Living Buddha, praying for the Enlightened One’s blessings. The altitude here is 3260m and, on this occasion, the temperature dropped to -27°C. The monks sat impassively throughout, seemingly oblivious to the blizzard.

When is it? The Great Monlam Festival is celebrated during the first lunar month of the Tibetan calendar (usually around February), heralding the start of the Tibetan New Year.

Good Friday, Antigua Guatemala, Guatemala

Tens of thousands of purple-robed penitents journey from all over Central America to participate in the Easter ceremonies here. At dawn, Roman Centurions march through the streets of the ancient capital of Guatemala, calling out the sentence for Jesus’s death.

Virgen del Carmen Festival,Paucartambo, Peru

Nestling in a valley below Mount Ausangate (6700m), the remote town of Paucartambo celebrates the Earth Mother, Patron Saint of the Mestizopopulation, during the Qechuamonth of “earthly purification”.

The festival dates from 1662 and for three days the town renews its faith, joy and hope for a better future. From the rooftops, mythical birds and animals attempt to attract the attention of the life-size image of the Virginas she is carried through the town.

When is it? The festival is held annually between 15–17 July.

Abbots Bromley Horn Dance, Staffordshire, England

The Horn Dance – an ancient fertility celebration – is believed to be part of a pagan hunting ritual with origins that can be traced back to Saxon times. It was probably first performed at the Berthelemy Fair near Burton-on-Trent in 1226. The six pairs of reindeer horns carried by the dancers have been carbon dated to 1065, around the time of the Norman Conquest. There are references in the Bible to the wearing of deer-horns as a sign of strength.

When is it? The ritual takes place on the Monday following the first Sunday after 4 September.

Phaung Daw U Festival, Lake Inle, Myanmar

The objects of the Intha people's veneration are five small statues of the Buddha dating from the twelfth century. They reside in thePhaung Daw U paya (pagoda), one of the three most sacred shrines in Myanmar. During the festival, a huge aquatic procession carries these statues to every village on the lake, providing an annual opportunity for the Intha people (meaning "sons of the lake") to pay homage to them.

When is it? The festival takes place for 18 days during the period of the full moon ofThadingyut; usually between September and November.

Black Snake Dance, Apenda Clan, Papua New Guinea

The Apenda Clan is a remote tribal group within Papua New Guinea. They attend annual gatherings called sing-sings, whose aim is to express their tribal solidarity and manpower. At the sing-sing in Morobe (near Leh) pictured below, the tribe perform the Black Snake Dance.

When is it? The Morobe sing-sing is usually celebrated between September and October. In 2017, it will be celebrated on 7–8 October.

Bull Jumping Ceremony (Ukuli Bula), Lower Omo Valley, Ethiopia

The Italian historian Carlo Conti Rossini describes this part of Ethiopia as a “Museum Of Peoples”; there are at least eight major tribal groups living here who, until recently, were largely untouched by outside influences. Ukuli Bulais a rite of passage to manhood (and marriage) for boys of the Hamar tribe. A key element of the ceremony is the whipping of young women related to the boy; the women use trumpets to indicate their desire to be whipped.

When is it? There are no set dates for this festival – boys of the Hamar tribe come of age all the time.