The Square Mile is one of London's great lies. Since its Roman conception, the City of London's metabolism has gone to pot, ballooning from half a square mile to its current 1.12 square miles.
But at least we know it's contained to the north of the Thames, right?
Not according to the small quadrilateral roped out in red by Google (see above); is it a gremlin in the system?
Indeed not. The red oddity demarcates the bridge head of Blackfriars Bridge — most of which lies within the City's boundaries. The dragon on the south side of the bridge marks roughly where Southwark becomes the City:
That said, a few feet further south of the dragon — and still officially within the City limits — resides Rennie Garden.
This small walled enclave, consisting of a couple of flower beds, two benches, and a City of London grit bin, is named after the engineer John Rennie. He was the man behind the previous iteration of London Bridge. Rennie also designed the former Southwark and Waterloo Bridges.
So why is his memorial garden at the end of a bridge he has nothing to do with?
Rennie Garden is the former site of Albion Mills — the looming symbol of industry that probably inspired William Blake's poem Jerusalem — and the machinery of which was designed by Rennie.
It was also where the word 'panorama' was coined, when Henry Aston Barker clambered onto the roof of the mill in 1790, to create a 360° painting of London.
The City of London Corporation took ownership of Rennie Garden in 1862 (at this time, Blackfriars Bridge was in a previous incarnation), and it's been part of the City ever since.
Blackfriars Bridge isn't the only bridge to fall wholly within the City boundary: London Bridge does too, as this map inside Rennie Garden shows:
Southwark Bridge (completed in 1921) and the Millennium Bridge (2000) presumably came too late to be considered part of the Square Mile.
Still, Southwark Bridge and Millennium Bridge — along with Tower Bridge, which is outside the City limits — are cared for by the City of London Corporation. Much of the money for upkeep is paid from the Bridge House Estates, a charity originally set up in the 13th century and still going strong.
The City is also responsible for various other swathes of London, such as Epping Forest and Hampstead Heath.
Next time you're crossing Blackfriars Bridge, take a moment to sit in Rennie Garden, and gaze across the Thames at the City... while also being in the City yourself.