Green square sign. It reads "Zona B1". It may be used in articles related to [[[:es:Metro de Madrid|Metro de Madrid]].
<a href="//commons.wikimedia.org/w/index.php?title=User:FedericoMP&amp;action=edit&amp;redlink=1" class="new" title="User:FedericoMP (page does not exist)">FedericoMP</a> (321 bytes)
2008-04-07
<span class="int-own-work" lang="en">Own work</span>