When you have spent more than 30 years taking photographs of festivals in 60-odd countries, found yourself in the middle of a crush of five million people in a dangerously small area, watched the sacred rituals of tribal societies under threat of extinction and seen monks and nuns having their hair pulled out as part of an initiation ceremony, it must be hard to name one single event that stands out in your mind.
However, for photographer Jeremy Hunter, the epic Arirang celebration of the birthday of Kim Il-sung North Korea last year was in a class of its own.
The event involved a cast of 150,000 in a dance and acrobatic display set against a pictorial backdrop of changing monumental images. The images were created by 50,000 teenage children, each one holding a flip chart and turning it at precisely the same moment to create massive, changing mosaic pictures.
"It is propaganda art at its absolute finest," says Hunter, whose work will form the basis of a major exhibition in Perth this summer. Describing the Arirang event, Hunter still sounds awestruck. "These children had rehearsed for 10 hours a day from February until August. Someone worked out that they would be required to spend 250 million man hours perfecting the synchronisation, because each flip chart contains about 170 A3-size pages.
"Without doubt, it's the most amazing spectacle I have witnessed in 35 years of global reportage."
With the death of Kim Jong Il last December, it has been made known that Arirang will never be celebrated again, which means that Hunter's images are an important historical record.
In fact, because of political changes, a number of the sights Hunter has recorded are no longer open to visitors or have been suppressed or discontinued. In his latest exhibition, Let's Celebrate 365, which opens in Perth on Thursday, this theme of societies in transition comes to the fore.
Not that creating an historical archive was his intention when he started taking photographs of festivals and rituals. Hunter, 68, made his name making TV commercials, many of which are famous. "I made some of the most iconic commercials of the last decades," he says simply. "The Lady Loves Milk Tray, Cadbury's Flake, Fairy Liquid, Heinz Means Beanz: you name it, I made it."
However, after 15 years, he needed a change and was "very lucky" to be offered a job as a reporter for Iranian television, even though he had no experience.
"I had literally gone from making Fairy Liquid commercials, in a couple of weeks, to interviewing Indira Gandhi, the most powerful woman in the world."
It was the mid-1970s and the pro-American Shah of Iran was still in power. For two years, Hunter fronted a weekly news programme and travelled the world. He started filming and taking photographs of festivals, initially to provide colourful sequences for his news reports, but increasingly as part of a personal project to document world cultures. After returning to the UK, he carried on taking every available opportunity to photograph festivals.
A number of them face an uncertain future. Take the bull-jumping ritual of the Nyangatom people of the Lower Omo Valley, Ethiopia, in which young men leap over bulls as a rite of passage. The Nyangatom are among 100,000 herdsmen who have lived "a very, very simple existence for centuries". The Ethiopian government, however, has leased huge tracts of the land to foreign investors, to produce sugar cane, while a vast hydroelectric project, the largest in Africa, will reduce the flow of the river Omo.
"The word is that this tribal society as we know it will probably disappear within the next five years," says Hunter.
Some of the sights he has seen have been extreme. In Karnataka, south-west India, he was honoured with an invitation to observe monks and nuns entering the ascetic life, who must develop an indifferent attitude to pleasure and pain as part of their initiation. They go through the Kesha Lochan, a ritual which involves having their hair pulled out by the roots. "That is very rare and I've never actually found anyone who's seen that as I have," says Hunter. It was "horrendous" to witness, he admits, but adds that it is seen as a devotional rite by those involved.
Then there was that visit to North Korea. Hunter managed to gain entry through a Beijing company. He was under escort at all times, but authorities could not hide the glimpses of real life he saw from the windows of the bus, such as hungry peasants gathering grass on the verges to supplement their meagre and insufficient government rations.
Hunter is passionate about religious and cultural tolerance. He does not adhere to any one faith but "cherry-picks" from what he sees. "I've built up a sort of multi-denominational belief," he says.
He has occasionally been in potentially dangerous situations, but in the midst of anxiety has found the greatest expressions of kindness and solidarity, most memorably in January 2010 when he attended the Biswa Itjema in Bangladesh, an alternative to the Hajj (pilgrimage to Mecca) for poor Bangladeshi Muslims. Five million devotees came to the banks of the river Turag just outside Dhaka, he explains. "There were only myself and a New Zealander colleague who were non-believers.
"I have been to many, many events. This was the one that, before I got to it, I was most frightened by, because the crush of people in one small place was just so huge. We had also been warned that it might be targeted by a suicide bomber.
"Being surrounded by five million people in a small area is beyond comprehension. Yet I was among Muslim devotees who were honoured that I wanted to be among them and they acted as a kind of shield to ensure that I didn't get crushed.
"It was one of the most humbling experiences I've ever been through."
Now Perth is to become a huge living gallery of Hunter's 30-year cultural journey. The main exhibition will be held at the Royal Scottish Geographical Society's visitor centre at the Fair Maid's House, but a further 25 photographs will be on display in cafes, shops and other public buildings. "Treasure maps" will be available for visitors.
Hunter is delighted that his first Scottish exhibition is to be hosted by the RSGS. However, with plans to photograph still more festivals in the pipeline (Benin is next, in January), it may not be his last.
Let's Celebrate 365 runs from July 12 until September 3, 12.30pm-4pm, Royal Scottish Geographical Society, The Fair Maid's House Visitors Centre, Lord John Murray House, 15-19 North Port, Perth. Jeremy Hunter's LC365 lecture slideshow will take place at 7.30pm, September 4, at Perth Concert Hall. Visit www.jeremyhunter.com.