The Niesen is the sharp, pyramid-like mountain south of Spiez, one of the most recognisable shapes around Lake Thun. From the summit, the view takes in the lake, the Bernese Alps, and the valleys leading towards the Simmental.
Most travellers reach it by the Niesenbahn funicular from Mülenen, a short trip from Spiez by train or bus. Hikers can make a harder day of it, but the lift is the sensible choice if you mainly want the view.