Tram Schwerin (Germany) at the 2007 built <a href="https://en.wikipedia.org/wiki/Bundesgartenschau" class="extiw" title="en:Bundesgartenschau">BUGA</a>-balloon loop
<a href="//commons.wikimedia.org/wiki/User:Proteg%C3%A9" title="User:Protegé">User:Protegé</a>
CC BY 2.5
photo taken by Protegé