You may also like these photo galleries
This is the second largest national park in the US, and it takes time to truly appreciate, writes Andrew Bain.
It's breakfast time in the Lamar Valley. Across the river from where I stand, a grizzly bear gnaws at a carcass. Coyotes hover in the sagebrush, and a bald eagle watches from the top of a dead tree.
A fox hurries down the road with a meal of chipmunks hanging from its mouth, and so many bison dot the valley it's like looking at paddocks of livestock. It's almost the full ensemble of Yellowstone National Park wildlife in this valley known as "America's Serengeti".
The Lamar Valley sits at the northern edge of the world's oldest national park, just outside the enormous caldera volcano that is the park's centrepiece. Drive a few minutes over Dunraven Pass and I can be back among geysers and boiling mud in this park that's like two places at once – African safari meets Rotorua.
Outside the caldera, in the Lamar Valley, Yellowstone is a place of bears and bison. Inside the caldera, it's a place of superlatives.
Mud pots gurgle like soup on a stove, steam gasps from the ground, and geysers dance like fountains.
About half the world's thermal features sit inside this supervolcano, where two magma chambers, said to contain more than 50,000 cubic kilometres of molten lava, sit as near as 10 kilometres below the Earth's surface.
Yellowstone holds 10,000 hot springs, 300 waterfalls and 300 geysers. Surrounding the most famous geyser, Old Faithful, is the greatest concentration of geysers – 200 in four square kilometres – in the world. The longest undammed river in the lower 48 states cuts a grand canyon of its own – the Grand Canyon of the Yellowstone – through the heart of the park.
It's a dynamic, changing place. There are thermal features that arose or changed after a massive 1959 earthquake. Geysers suddenly started spouting; others changed their regularity, including Old Faithful, which suddenly became not so faithful.
If you think the Earth is a static place, Yellowstone is the antidote. If you believe in the epic power of nature, it's the confirmation.
Yellowstone is the second largest national park in the lower 48, behind Death Valley National Park, and like other large parks such as Kakadu, it takes time to truly appreciate.
Yellowstone doesn't smack you between the eyes like Yosemite or Zion national parks. Its bulk is covered in pine trees, and there is the ever-fluky nature of wildlife viewing. A place where grizzly bears or wolves roam one morning might be bare of all but a few bison the next. But over much of the park hang perpetual clouds of steam, and the farty scent of sulphur stings the eyes.
The last great eruption here – the one that created the Yellowstone Caldera – was 640,000 years ago, but as the land seems to move and melt around you, it's hard not to wonder about the next one.
The park, which is almost as large as Lebanon, is divided into sections, each one framed around a "village" and some of the grandest old hotels in the US national park system.
I enter the park from the south, where Lake Yellowstone Hotel commands the shores of Yellowstone Lake. Built in 1891, it was the original grand park hotel.
With the presence of a southern plantation house, it still exudes an ancient grandeur that's seemingly appreciated by more than just its human visitors. As we leave the hotel, traffic is stalled as a herd of bison ambles across the road beside the hotel.
When the traffic jam clears, we drive north, heading into the "place where Hell bubbles up", as described by one of the first Europeans to travel through the caldera.
At its heart, an almost unbroken run of thermal activity stretches along the road from Fountain Paint Pots to Old Faithful. Fountain Paint Pots is a greatest hits album of geothermal activity, making it the perfect introduction to thermal life in Yellowstone. Mud pots gurgle like soup on a stove, steam gasps from the ground, and geysers dance like fountains.
It's at once a white desert and the most colourful place imaginable. The ground is bleached by sulphuric acid, and dead trees angle out of the earth like the bones of a dead animal.
But within this landscape are blue pools that somehow dribble luminous orange stains across the earth. For good measure, a herd of bison – fast becoming the ubiquitous seagulls of Yellowstone – grazes at its edges.
A boardwalk circuits through the Fountain Paint Pots, raised off the ground because the earth here is a fragile crust that can be as dangerous as the wildlife. At one spot beside the boardwalk is a hole where, four years ago, a bison fell through the earth. Ever since, the hole has been widening and is now a boiling mud pot.
Fifteen kilometres down the road, Old Faithful is Yellowstone's leading lady. This geyser was named because it blew with such religious regularity – 21 times a day – but after the 1959 Hebden Lake earthquake it became more difficult to precisely predict its routine.
Eruptions can now only be forecast to within 10 minutes, with the geyser blowing about every 90 minutes, shooting water up to 50 metres into the sky, inevitably before a crowd worthy of a sporting event.
"We say that it's never been early and it's never been late," park guide Tom says. "It's just that the people who forecast it sometimes get it wrong."
One forecast that proves correct comes the following morning. At the edge of Slough Creek, near the Lamar Valley, we're watching as another herd of bison streams along the waterway's banks.
"There was a grizzly just up the road a bit earlier," a woman says, and off we charge, one alpha species in pursuit of another. By the old ranger station at Buffalo Ranch we join a herd of our own as a crowd gathers along the road edge. A forest of spotting scopes points across the river at the breakfasting bear, hunkered down in the sagebrush grasslands.
The animal is just a tiny dot in this most massive and unstable of landscapes, but it's another wild moment in this most wild of national parks.
Qantas flies direct daily (except Saturday) to San Francisco from Sydney, with United Airlines connecting San Francisco direct to Bozeman, Montana, one of the nearest airports to Yellowstone. qantas.com; united.com
Xanterra is the concessionaire in Yellowstone, and in summer it operates a dozen day trips around the park in its trademark yellow buses. See yellowstonenationalparklodges.com/things-to-do/summer-things-to-do/adventures-on-land.
Staying & Eating There
Each village has accommodation and dining options, though Yellowstone is no gourmet destination. Canyon is the most central village. Three new lodge buildings were constructed here in 2015, adding a touch of class to the park. yellowstonenationalparklodges.com/lodging/summer-lodges/canyon-lodge-cabins
The writer travelled courtesy of Visit the USA and The Real America.