London used to be surrounded by a wall that was built by the Romans around 200 AD and had later medieval additions. That very old London still is. But the wall has got lost and you have to look carefully for remnants – of which there are still plenty.
Its course runs in a roughly horseshoe shape from around Blackfriars station northwards via the Old Bailey and the Museum of London before turning east along the road called London Wall and then meandering its way to the Tower of London. Following it is like chasing a serpent which disappears underground only to reappear before diving out of sight again. The locations of three of the most visible bits are as follows:
Bank of America Merrill Lynch, Newgate Street.
It would be difficult to find a more dramatic contrast between old and new London than this. Above ground, the throbbing trading floors of the US investment bank. Below it, an ancient section of Roman-built London Wall, now lying 20 feet beneath the streets of the city having been buried under layers of City development. The wall helped protect the City of London from its enemies.
You need to have permission to see the full glory of this extensive chunk of wall, but you can get a good idea of what it is like through a window in the square. Go down an alley next to the Viaduct pub at the junction of Giltspur Street with Newgate Street (where it joins High Holborn). Walk down the alley and turn left into the courtyard opposite Caffe Nero. A little way along on the left you can peer through the window and see the wall. This is what remains of a four metre high wall and bastion built from stones carried by sea from Kent.
There is another bit of the wall in the basement of the Old Bailey nearby along the passageway where prisoners once walked to the gallows, but you will need to be on one of the official Old Bailey tours in order to see it.
Museum of London Archaeology (MOLA) area.
This is where one of the bastions or forts was located, which defended the wall. Start at Noble Street where remnants are visible (with a lot more underneath if you catch one of the MOLA tours). Then, on the other side of London Wall, there are more remains of the bastion and wall. If you double back and go down Wood Street to the churchyard of St Giles Cripplegate there is a generous expanse of the medievalised wall. There is yet another section in the underground car park, which runs the length of this part of London Wall road. Further along London Wall, part of the medieval wall (with Roman foundations) has been incorporated at All Hallows church.
Tower Hill Underground station.
The most dramatic section of surviving wall can be seen when you are exiting the station (see photo at the top of this post). It is the eastern end of it, Roman and Medieval, 33 yards long and standing at pretty much its full height of almost 12 yards. If you navigate around Coopers Row and the Grange Hotel, you can see more of the wall subtly blending in with modern buildings. A little further on, at One America Square, there is another large section, preserved on the lower floor of a commercial building.