“The Tasman Glacier is a predictably spectacular sweep of ice, but further down it's downright ugly. Normally as a glacier retreats it melts back up the mountain, but the Tasman is unusual because its last few kilometres are almost horizontal. In recent decades it has melted from the top down, exposing a jumble of stones, rocks and boulders and forming a lake. In other words, in its 'ablation zone' (where it melts), the Tasman is covered in a solid mass of debris, which slows down its melting rate and makes it unsightly.”
For me it was really impressive, you can clearly see how the Glacier is cutting away at the mountains and what an unstoppable force it is.