The bridge
South Bridge Edinburgh: the viaduct you cannot see
Thousands of people walk along the South Bridge every hour and almost none of them know they are on a bridge. It has nineteen arches, it was finished in 1788, and it is completely hidden by the buildings put up against it on both sides. Only one arch is visible from the street. The vaults everyone tours are the space inside the other eighteen.
Quick answer
The South Bridge is a nineteen-arch viaduct in Edinburgh, completed in 1788, which carries a street across the Cowgate valley. Buildings were constructed flush against both sides, so only one arch — the one over the Cowgate — can be seen from street level. The chambers inside the arches became the Edinburgh vaults, let to tradesmen for about thirty years before damp emptied them.
The South Bridge, at a glance
- Completed
- 1788after roughly two years of building
- Arches
- Nineteencarrying the street across the Cowgate valley
- Visible from the street
- Onethe arch over the Cowgate
- Why hidden
- Buildingsput up flush against both sides
- Inside the arches
- ~120 chambersin places four levels deep
- Chambers let as
- Workshops and storageplus taverns, for about thirty years
- Abandoned by
- The 1820sno drainage, no ventilation, constant damp
- Excavated
- The 1980safter more than a century of rubble
- Access today
- Guided toursthe chambers are private property
- Tours from
- $20starting on the Royal Mile
Why it exists
Why was the South Bridge built?
A viaduct built to cross a valley, then swallowed by the buildings put against it.
Because Edinburgh had run out of room and could only grow across valleys.
The Old Town occupies a narrow ridge running down from the castle. On either side the ground drops away sharply — to the north into what was then the Nor Loch, to the south into the Cowgate valley. By the 1780s the city was expanding in both directions and needed road links that did not involve descending one side of a valley and climbing the other.
The North Bridge came first. The South Bridge followed, completed in 1788, carrying a new street southward from the High Street towards the university. It is a viaduct of nineteen arches, and if you could see it from the side it would look like a Roman aqueduct dropped into a city.
You cannot see it from the side, and that was deliberate. The value of the new street was its frontage, so buildings were run up against the bridge on both flanks from the valley floor to street level. The viaduct disappeared inside a wall of tenements and shops within a few years of being finished, and it has stayed hidden ever since.
Seeing it
Five ways to see the South Bridge for what it is
All five are free, and the first one takes about ninety seconds.
- Walk down to the Cowgate and look up
The one surviving visible arch spans the Cowgate. Stand under it and the scale of what is above you is suddenly obvious.
- Notice the level change on Blair Street
The side streets running off South Bridge drop away steeply. That drop is the valley the bridge is crossing.
- Look at the doorways on Niddry Street
Half a floor down from the main street in places. The Old Town’s vertical geometry is nowhere clearer.
- Count the frontages between the Tron and Chambers Street
Every one of them is standing on or against the viaduct. The street is not on the ground at any point along that stretch.
- Go inside one of the arches
Which is the only way to feel it properly, and requires a tour. From $20, and the chambers are genuinely inside the 1788 structure.
The chambers inside those arches are what every vaults tour in the city is selling.
The vaults, in full→Every trip, current fare
Tours that take you inside the bridge
Twelve tours, cheapest first, with which underground each one enters. Seven of them go into the chambers inside the South Bridge itself.
| Tour | Length | Price | Which underground | Cost per hour | Rating |
|---|---|---|---|---|---|
| Old Town & Underground Ghost TourThe cheapest hour under the bridge | 1 h | $20 | The vaults | $20.00 | 4.4 · 1,871 |
| The Edinburgh DungeonAn attraction with actors, not a historical site | 80 min | $24 | None — an attraction | $18.00 | 4.6 · 1,716 |
| Evening Underground Ghost TourThe evening slot in the South Bridge vaults | 75 min | $24 | The vaults | $19.20 | 4.4 · 4,063 |
| Old Town & Underground Historical TourThe bridge and the chambers as the actual subject | 1.5 h | $25 | The vaults | $16.67 | 4.4 · 2,068 |
| Underground Vaults TourThe standard vaults tour, most reviewed in the city | 1 h | $25 | The vaults | $25.00 | 4.5 · 12,500 |
| Haunted Vaults & Graveyard TourA kirkyard and the vaults in one evening | 1.5 h | $27 | The vaults | $18.00 | 4.6 · 7,277 |
| Late-Night Vaults Terror TourThe late slot, run harder | 75 min | $27 | The vaults | $21.60 | 4.6 · 4,571 |
| Extreme Paranormal Underground Ghost TourThe vaults and a kirkyard, played for fright | 75 min | $27 | Vaults + kirkyard | $21.60 | 4.3 · 885 |
| Multi-Sensory Haunted UndergroundThe original Blair Street vaults tour | 75 min | $34 | Blair Street vaults | $27.20 | 4.5 · 2,754 |
| Small-Group Historic Vaults TourThe Blair Street chambers, in a small group | 75 min | $34 | Blair Street vaults | $27.20 | 4.7 · 614 |
| Real Mary King's CloseA street the city built over in 1753 | 1 h | $36 | Mary King's Close | $36.00 | 4.7 · 4,457 |
| Vaults Evening Tour with WhiskyTwo hours, ending with a dram underground | 2 h | $39 | The vaults | $19.50 | 4.7 · 2,798 |
Common questions
The South Bridge, answered
What is the South Bridge in Edinburgh?
A nineteen-arch viaduct completed in 1788 that carries a street across the Cowgate valley, linking the High Street southward towards the university. Buildings were put up against both sides, so it is almost entirely hidden.
Why can you not see the South Bridge?
Because tenements and shops were built flush against both flanks within a few years of it being finished. Only one arch, the one spanning the Cowgate, is still visible from street level.
How many arches does the South Bridge have?
Nineteen. The chambers built inside them are what the city now calls the Edinburgh vaults.
When was the South Bridge built?
It was completed in 1788, a few years after the North Bridge on the other side of the ridge.
Can you go inside the South Bridge?
Yes, on a guided tour of the vaults. The chambers inside the arches are private property behind locked doors, and tours run from the Royal Mile starting at $20.
Is the South Bridge the same as the Edinburgh vaults?
The vaults are inside the South Bridge. The bridge is the structure; the vaults are the rooms that were walled off within its arches and let out as commercial space.
Go deeper
More on the Edinburgh underground
The Edinburgh vaults
Built in 1788, used for thirty years, abandoned, and dug out again.
The closeReal Mary King's Close
A street built over in 1753 and lived in until 1902.
The whole thingThe underground city
What is actually beneath the Old Town, and what is only a story.
Which vaultsBlair Street or Niddry Street
Different chambers under the same bridge, and who runs which.
Side by sideVaults or the close?
The comparison everybody makes, with a straight verdict.
Vaults toursEvery vaults tour compared
Seven tours into the same chambers, and what separates them.
