Day 21 and we’re delving into the origins of a square mile of offices.

The City of London is pretty much all office blocks now, a process with its roots in the 19th century, but where did it all begin and which company was behind it?

They were once behind a door on this site, any ideas? (If you can make out that fragment of a current company logo above the door that might help!).

Click the pic to reveal the answer!

Find out more on Dave Charnick’s Dickens of a City tour.