<b>Burner of a hot-air balloon</b><br>
View into a balloon with one ignited burner. The left burner is for the other 2 of 4 gas cylinders. In case of emergency (rapid sinking &gt;3m/s) both burners can be ignited.
<a href="//commons.wikimedia.org/wiki/User:Der_Keks" title="User:Der Keks">Der Keks</a>
<span class="int-own-work" lang="en">Own work</span>