took a three-day camping trip in California's Yosemite Valley.

President Theodore Roosevelt slept in a grove of towering Sequoia trees,

camped in a snowstorm, and spent hours talking around the campfire

with his host and guide, conservationist John Muir.

Roosevelt famously loved the outdoors,

but Muir had invited him there for more than just camping:

Yosemite was in danger.

Though Yosemite became protected land in 1864,

the valley was still at risk for overdevelopment in 1903.

It was at the heart of a decades-old struggle to set aside land

for both preservation and public use—

two goals that were much easier said than done.

The battle over Yosemite began with the 1849 gold rush,

when miners surged west, seeking gold in the Sierra Nevada foothills.

In 1851, a state-sanctioned militia,

drove the Ahwahneechee tribe from Yosemite Valley.

Those who managed to return witnessed white settlers claiming the land,

felling giant sequoias, and building hotels and saloons.

In response, a small group of concerned Californians

lobbied senator John Conness to protect the valley from private interests.

In 1864, Congress passed Conness' bill,

granting the Yosemite Valley to the State of California,

marking the first time the U.S. government brought land under public protection.

But the management of that land remained an open question,

one that would only become more complicated

as more lands came under similar protection.

Seven years later, geologist Ferdinand Hayden

led an expedition to the Yellowstone Plateau,

which many Native American tribes used for ceremonies, hunting, and trade.

The expedition's scientists and artists brought back news

of spectacular geysers and hot springs,

inspiring widespread support to bring Yellowstone under government protection—

and restrict native people's access to the land.

However, unlike Yosemite, Yellowstone couldn't be granted to a state—

it was part of three U.S. territories that hadn't become states yet.

Instead, Congress brought Yellowstone under federal stewardship in 1872,

creating the world's first true National Park.

During his presidency, Teddy Roosevelt was instrumental

in expanding the lands under public protection.

By 1916, there were fifteen national parks.

But the problem of management remained unsolved,

and maintenance of the park was handled haphazardly

over multiple government departments.

Straightforward tasks like building roads and hiring personnel

required inefficient bureaucratic maneuvering.

None of the departments had set rules for conduct in the park,

so hunters killed park wildlife, cattle overgrazed fields,

and visitors vandalized landmarks.

The solution came from Canada,

which had a highly effective centralized park service.

In 1916, the United States established the National Park Service

based on this model.

To this day, the mission for the park service is comprised of two goals

that sometimes conflict:

to conserve the parks for the future

and to allow the public to enjoy them.

That's a delicate balancing act: roads, trails, and other infrastructure

make the parks accessible to visitors, but also alter the landscape,

while visitors themselves can contribute to pollution, erosion,

and damage of delicate ecosystems.

The very history of preservation can also be at odds with this mission.

Many parks were not, at the time of their founding,

the uninhabited wilderness that's become the standard for their preservation.

Instead, many were homes or places of worship for native peoples,

who lost access to these lands in the name of public use.

Only recently has the National Park Service

begun to reckon with this legacy and engage Native Americans

in park management.

Around the world, indigenous communities play crucial roles

in land management and preservation.

Today, there are thousands of national parks worldwide,

and each must balance public use with historical and ecological preservation.

Parks in New Zealand, Iceland, Australia, and South Africa

have experienced severe erosion as visitor numbers have skyrocketed.

Some, like Mu Ko Similan National Park in Thailand,

have closed sections to tourists entirely to allow the ecosystem to recover.

National Parks have preserved irreplaceable landscapes

for future generations.

They also force us to reckon with hard questions:

what are our responsibilities to this planet, and to each other?