The collision is recent, and it is strange. For most of the twentieth century, pumas were rare here, shot to protect sheep on the ranches that once spread across this country. When the guns fell silent and the land became a park, the cats returned to a coast they had not patrolled in living memory. Waiting for them was a colony of Magellanic penguins - clumsy on land, defenseless against a predator that had never been part of their world. Researchers tracking the cougars discovered that the seabirds had become a seasonal feast, and that the feast was changing the cats themselves. Famously solitary animals began tolerating one another near the nesting grounds. A new ecological relationship was being written in real time, on a beach at the bottom of the Americas.

Monte León spreads across more than 62,000 hectares, and it holds three landscapes stacked against each other. Inland lies the steppe - rolling, grass-blanketed, endless. In spring the dry hills flush with small flowers and herbs, and guanacos, the wild cousins of the llama, graze where sheep once did. Then the land simply stops. High sandstone cliffs drop to a ragged Atlantic shore, thirty-six kilometers of rocky beach where sea lions haul out to sun themselves and penguins crowd the dunes. Offshore, southern right whales surface close enough to watch from the clifftops. The signature landmark gives the park its name: a rock formation called Cabeza de León, the Lion's Head, which imaginative eyes have decided looks exactly like a great cat staring out to sea.

Each October, the Magellanic penguins come ashore to nest and molt, and the dunes fill with the noise and bustle of a colony tens of thousands strong. They dig burrows, raise chicks, and shed their feathers in the brief Patagonian summer before the cold drives them back to sea. Along the Penguin Trail, a footpath that climbs over rocky, steep ground from the highway, interpretive signs explain the birds and the fragile shore they depend on. The reward at the top is a viewpoint over the whole churning colony. Three species of cormorant nest on the cliffs and islands, and rheas - large flightless birds of the open plains - stride through the grass inland. The whole place runs on the rhythm of arrivals and departures, of animals that come for a season and then vanish.

People have known this coast for a very long time. Hunter-gatherers lived here roughly ten thousand years ago, leaving stone tools in caves that archaeologists still study. Much later, through the twentieth century, the land was a sheep ranch called Estancia Monte León. The old ranch house now serves as the park's administration building, and a former shearing shed has become an interpretive center, its history of wool and isolation folded into the new story of conservation. The land was bought up between 1996 and 2002 and handed to Argentina's national parks administration. In 2004, Monte León was formally created - and named the country's first coastal national park, the first place where Argentina extended its protection from the land out into the sea itself.