Morning: Cueva del Milodón
The first stop comes early: the Monumento Natural Cueva del Milodón, tucked against the flanks of Cerro Benítez some 24 kilometres northwest of Puerto Natales. The cave — a single enormous chamber 30 metres high, 50 metres wide, and 200 metres deep — was discovered in 1895 by the German settler Hermann Eberhard, who found a large piece of apparently fresh animal hide on the cave floor. It was subsequently identified as belonging to Mylodon darwini, a ground sloth roughly twice the height of a person that roamed Patagonia until around 10,000 years ago. Other remains found here include the dwarf horse Hippidion, the saber-toothed cat Smilodon, and evidence of human habitation: fire-fractured rock, lithic tools, and human remains dating back over 12,000 years.
A life-size fibreglass replica of the Milodón stands at the cave mouth. Beyond it, an interpretive circuit connects the main cave with the smaller Cueva Chica and Cueva del Medio, as well as the eroded conglomerate formation known as the Silla del Diablo (Devil's Chair). An environmental information centre and basic visitor facilities are available on site.