Trummelbach waterfalls are under the cave waterfalls situated in a beautiful valley of Lauterbrunnen. You can take a lift to go up to certain height or else hike the cliff. Both options are worth it. I took lift while going up and climbed down while coming back, because it was my last spot of the day and I was so tired. There are 7 levels of this waterfall inside the cave. It looks magnificent and is surprisingly cold. A must visit if you are in Switzerland!