Lago Grey is the park's glacial lake, and unlike the warm-looking blues elsewhere in Torres del Paine it is cold grey-green, scattered with icebergs that have calved from the Grey Glacier at its far end. The glacier is an outlet of the Southern Patagonian Ice Field, the largest mass of ice in the southern hemisphere outside Antarctica, and the bergs drift down the lake on the wind, some as blue as sapphire, some striped with dust and sediment. They wash up on a beach of dark pebbles near the lodge, where you can stand close enough to hear them crackle.
The approach is the best part of the day. The road from the main park route runs west over gravel, passing small lakes, then dropping through windswept scrub toward the shore. Views of the Cuernos stay with you for much of the way, and on a clear morning the whole massif seems to float above the plain. The surface is variable, so take it gently, and be careful on wet days when the clay turns slick. The wind often funnels along the shore, making it hard to stay upright on the bike when you stop, so park with some thought.
Boat trips run to the glacier front from near the lodge, and walkers can follow a trail to a viewpoint above the beach. Even if you do neither, a walk along the pebbles with the icebergs at your feet is worth the cold. The ice has been retreating in recent decades, but the scale is still enormous, and the roar of a calving face can reach you across the water.
Wildlife in the area includes foxes, guanacos and the occasional puma, which locals say is more common than it used to be, though you are unlikely to see one. The southern beech forest in the sheltered folds of the land is a mix of lenga and ñire, turning copper and red in autumn, which is a strong reason to visit in March or April.
The nearest pumps are in Puerto Natales, so the same rule applies as elsewhere in the park: leave town with a full tank. The hotel by the lake offers meals and coffee, and the cold wind makes a hot drink very welcome.