Part of the cutter head from the front of the TBM (Tunnel Boreing Machine) used to drive the twin tunnels under the river Thames from Island Gardens to Greenwich exhibited at Cutty Sark DLR station.
<a href="//commons.wikimedia.org/wiki/User:Oxyman" title="User:Oxyman">oyxman</a>
CC BY 2.5
<span class="int-own-work" lang="en">Own work</span>