Zermatt, Alps, Switzerland
The Matterhorn is prone to clouds due to its exposed location, so there are only a couple of days in the year, where no banner clouds form over the course of the day. These banner clouds are caused by air flowing around the mountain, thus creating vortices, conducting condensation on the lee side; usually the eastern face.
At full resolution, you can even see the Solvay Hut, located on the Hörnli ridge at 4,003 m (13,133 ft) which is to be used only in case of emergency.
