A firepit in Sihlwald, along the Spinnerweg in Tannboden.  When the picture was taken, lighting fires was temporarily forbidden due to a drought during the preceding weeks; this is what the yellow sign says.
<a href="//commons.wikimedia.org/wiki/User:Domob" title="User:Domob">Daniel Kraft</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>