Tunnel under water surface (for <a href="https://en.wikipedia.org/wiki/route_diagram_template" class="extiw" title="w:route diagram template">route diagram template</a>)
<a href="//commons.wikimedia.org/wiki/User:T0118163" title="User:T0118163">T0118163</a>
<span class="int-own-work" lang="en">Own work</span>