English: Thousands of people walk past this red object embedded in the tunnel between the Waterloo & City and Central lines at Bank station every day without realising what it is. It's a piece of history - the original Greathead tunnelling shield which was used in the late 1890's for digging what is now the Waterloo and City Line. When the tunnel reached Bank it kept going for a little longer in order to bore a siding, then was abandoned at the end and remained unseen until the siding was converted into a passenger walkway a few years ago. This was all dug by men with pickaxes and shovels working in wet conditions under compressed air, not by machine.