Metro tunnel start/end on 90° turn.
<a href="//commons.wikimedia.org/w/index.php?title=User:%E5%8C%97%E5%B7%B7%E7%8C%AB%E7%9C%A0&amp;action=edit&amp;redlink=1" class="new" title="User:北巷猫眠 (page does not exist)">北巷猫眠</a>
<span class="int-own-work" lang="en">Own work</span>