Today you’ll see the sculpted geological formations of the Marble Caves, which are an undisputed highlight of the Carretera Austral. Located on the vast Lago General Carrera Lake, these bright blue and grey caves have been formed by over 6000 years of erosion and are truly mesmerising. This excursion involves taking a boat trip from the tiny dock at Puerto Tranquilo, although if you’d prefer you can even visit by kayak to get a different perspective of the swirling patterns inside the caves.