Despite decades of change and development, nomads still migrate to the Tibetan Plateau every summer, from where China Correspondent Stephen McDonell reports.
There was a time here when tribal Tibetans roamed across a vast dramatic landscape with no specific place to call home.
For generation after generation they had lived as nomads, sleeping where they made camp.
They kept their livestock moving, chasing the fresh pastures that became available as the seasons changed.
The limits of their territory were identified by mountains and rivers, and their nomadic existence permeated all aspects of their culture.
In 2016, you might expect this lifestyle to have been fully extinguished, yet it hasn't been. Not quite. However, what's left of it is now coming under considerable pressure.
We set out to visit one Tibetan community in Aba region.
This place came to world attention in recent years as the centre of a wave of self-immolation suicide protests. In Tibetan towns, nearly 150 people, mostly monks and nuns, set fire to themselves in protest at the impact of Beijing's rule - the largest number of them in Aba.
For this reason, security has been tight in the area for years. But, as the self-immolations have slowed, we hoped to be better able to reach remote communities and speak to people.
The central Chinese province of Sichuan - of which Aba is a district - is quintessential China. It's the home of pandas and spicy food.
If you look at a map its virtually in the middle of the country.
Yet if you drive out of the regional capital Chengdu and head west, it's not long before you enter another world. The road heads up and up until you reach the Tibetan Plateau.
When people speak about Tibet they often mean what's called the Tibetan Autonomous Region (TAR). This is the area foreigners are not allowed to enter without special permission, where reporters are rarely granted access and, if they ever are allowed in, must be accompanied by a minder at all times.
However, the massive area where ethnic Tibetans actually live is twice as big as the TAR, spreading out across the plateau and dipping into Yunnan, Qinghai, Gansu and Sichuan.
On arrival in what you might call the Tibetan zone we are quickly spotted by police.
The authorities have been expecting us. They know we have been in contact with locals trying to line up interviews and to prepare logistics for the trip. They have already sent messages back to us via these same locals saying we are not welcome, suggesting we go elsewhere.
We have barely unpacked when government officials arrive for a chat.
What are we doing here? What are our plans?
We explain that we are here at this specific time to film the annual movement of herdsmen who will drive their yaks up into the hills where they will live for the summer months.
They listen, appear friendly enough and don't kick us out. But the next day when we speak to those preparing to make the journey, the government will have its people listening in.
We get up before the sun hits the grassland.
There are villages nearby and these days - during the freezing winter months at least - most people here live in fixed dwellings.
Following a deliberate government policy of relocation, Tibetans have moved into the towns. Critics say this has been a control mechanism which allows the authorities to be able to track people more easily. The Communist Party says it was done to improve people's living standards, nothing more.
So, for much of the year, people have televisions, fridges and electrical lights. But when the summer comes they head for the hills - back to the land of their forebears.
"Nomads here are nomads to the bottom of our hearts," Kalsang Gyatso tells us. "We lived like this from ancient times. Actually we don't like being in houses."
We meet him and other family members rounding up their yaks and pushing them into a pen. Soon they, like all their neighbouring herdsmen, will follow the same route as every year and drive their livestock into the mountains where the grass hasn't been touched for months.
"If we don't go to the summer grasslands and just stay in the winter fields there will be no food left for the yaks. When they have new grass to eat, our animals will grow fat and they'll produce enough milk."
He also tells us that the summer pastures have medicinal flowers which the yaks need to eat in order to stay healthy.
The government official who had been standing in the field and listening to our interview suddenly disappears. Perhaps he realised that our story really is about what we said it was about and that it's not hurting anyone to speak about these matters.
Next to Kalsang Gyatso's place runs a recently laid tar road and along it the sound of hundreds of hooves can be heard. The migration is on!
Cars and trucks must part a sea of animals in order to get through. Most drivers just stop and wait for the beasts to pass.
The Tibetans are on horseback, calling and whistling to keep their livestock moving. Some of the yaks carry the bedding they'll need upon arrival as well as other bits and pieces for camping.
One young man speaks to us as he rides past. He says they must move now in order to make the most of new grass and provide for their families and that the dates for the journey are actually fixed by government regulations.
I ask how he feels getting back to the old ways at least for a few months, expecting a description of the rich ancient culture again flowing through his veins. "I'm a little bit tired," he says.
As we follow group after group heading further to the west we reach… a grassland adventure park.
It is being built smack in the middle of the main migration route and has already been opened. Eventually this attraction will be able to handle thousands of tourists on any given day.
We watch as yaks in their hundreds are pushed through the car park, under the main gate, past the turnstiles and soon they are surrounding the tourist buses carrying ethnic Han Chinese travellers in search of an awe-inspiring Tibetan experience.
China's Tibetan areas have been hotbeds of rebellion in the past, with some blaming Beijing for restrictions on Tibetan Buddhism, language and culture.
The government's answer: development.
We board one of the buses and speak to those taking photos of the Tibetans riding along outside.
"Up here it's exactly the eating a mouthful of meat, drinking a mouthful of wine plateau feeling that I wanted," says one woman.
"It feels like another world. I feel stronger about Tibetan culture because Tibetans are purer and lead a more simple life," says another and her friend nods.
They seem to have genuine affection for the people who call this place home and inside the adventure park they will come into contact with the Tibetans who have been employed here.
The herding communities, however, are divided about whether the explosion in tourist numbers is such a good thing.
Even the Tibetans who have opened small guest lodges with areas for camping are worried that their once pristine environment is gradually being overrun.
Tshe Bdag Skyabs has been travelling with his animals for two days.
"On the one hand, people's incomes have increased and transportation is more convenient," he says. "But the environmental harm from development has been huge."
Eventually he, his family and 400 yaks pass the tourist park and the outer limit of modern existence.
They arrive at the untainted expanse of the high mountain grasslands.
Here there are no shops, no roads, no tourists, but there is the space of their ancestors.
"When I make it here my mood is very good, exceptionally good," he tells us. "When city people come here they will also feel happy because of the fresh air and the smell of wildflowers. It's like a fairyland."
They will stay here until September. They will walk with bare feet in order to preserve the flowers that their yaks need to eat. They will milk their animals to make butter tea and cheese. And when the weather starts getting cold, they'll head back down the mountain, to return again next year.
When a traditional way of life collides with a massive influx of tourism it's always going to be good and bad.
You can only hope that the benefits outweigh any pitfalls.
But, when it comes to the grassland Tibetans - if what we have seen is anything to go by - despite everything that the modern world is throwing at them, their culture does appear to remain remarkably resilient.
At least, for these communities. At least, for the time being.