Aisén del General Carlos Ibañez del Campo

The Marble Caves (Capillas de Mármol) are one of the most surreal sights on the Carretera Austral — a formation of marble caverns, columns and tunnels carved over millennia by the waves of General Carrera Lake, whose extraordinary turquoise and cobalt waters reflect and swirl through the pale stone in constantly shifting patterns. Small boats and kayaks depart from the lakeside village of Puerto Río Tranquilo to weave through the caves and chapels (the light and water colour are best on a calm, sunny morning), and the lake itself — shared with Argentina and South America's second-largest — is a striking turquoise from glacial sediment, ringed by mountains. Puerto Río Tranquilo has grown into a small but well-equipped base for the caves and for excursions to the nearby San Rafael and Exploradores glaciers, part of the vast Northern Patagonian Ice Field.

Cerro Castillo — the “castle hill” — is a jagged, spire-topped granite massif that many consider Patagonia's most dramatic mountain after the Paine towers, and its national park has become a serious rival trekking destination without the crowds of the more famous park to the south. A multi-day circuit trek (typically three to four days) winds through lenga forest, past turquoise lakes and over a high pass beneath the peak's sheer granite walls, rewarding experienced hikers with some of the wildest scenery on the entire Carretera Austral. Shorter day hikes from the park's entrances offer a taste of the same landscape for those without the time for the full trek. The park sits a short drive from Coyhaique, the regional capital, making it an accessible add-on for travellers exploring the highway's central section.

Further south, Patagonia National Park tells one of Chilean conservation's great stories — a former sheep ranch in the Chacabuco Valley, rewilded over decades through a major private initiative and later donated to the state, now protecting wide-open Patagonian steppe grazed by large herds of guanaco and home to one of the largest surviving populations of the endangered huemul deer, Chile's national animal. Its visitor centre and trails, framed by mountains on both sides of the valley, make it one of the most rewarding wildlife-watching stops on the Carretera Austral. Nearer the coast, the Queulat National Park protects a very different spectacle: the Ventisquero Colgante, a hanging glacier draped over a sheer rock face, with meltwater plunging in waterfalls to a lake far below — reached by an easy trail and lookout points, or by boat across the lake for a closer view. Both parks reward the extra driving time the southern Carretera Austral demands.