Skip to content
DE
ShortlistSign in
List a propertyFind a property
Shortlist

Sources for the video

Beneath Vienna: as deep as it goes

Almost twelve metres beneath Stephansplatz lies a chapel. From there the video goes down layer by layer, as deep as it goes. These are its sources.

Also onInstagramTikTokYouTubeYouTube, long video

Video · 2:16 · with sound, in German

What the video shows

Just beneath the paving lie the walls of the Magdalene Chapel. It burned down in 1781, and its rubble was used to fill the Virgil Chapel below, a room from the 13th century. It was forgotten for almost 200 years and dug out again in 1973 during construction of the U-Bahn. Its floor lies 11.5 m below the square.

Beneath the surrounding houses lie old cellars, some of them two storeys deep. Right next to them, beneath the cathedral and part of the square, lie the catacombs: more than ten thousand people were buried there between 1745 and 1783. How deep they lie is not reliably recorded anywhere; the cathedral only gives the number of steps.

At the edge of the square the sewer runs about 7 m deep. Next to it is the U3, whose tracks lie one above the other at about 12 and 18 m, and the U1 platform at 25 m. From about 13 m, groundwater fills the gravel.

At almost 16 m the gravel ends. Below lies Tegel, compacted mud from the bottom of a lake that lay here about eleven million years ago. From about 100 m come the deposits of an even older sea, twelve to sixteen million years ago. St. Stephen’s Cathedral itself is built almost entirely of Leitha limestone, which formed on the shores of this sea.

Nobody has yet drilled down to the bedrock beneath Stephansplatz; the deepest boreholes in the inner city reach 332 and 365 m. In the east the layers lie much deeper. In Eßling in the 22nd district, a well was drilled for hot water in 2012, 4,180 m deep, at an angle and therefore 4,224 m long. At the very bottom came the rock of the Alps, which let no water through. Higher up, hot water was found; Vienna plans to heat with water from this layer soon.

Sources and image credits

Data

For the film we cropped, converted and redrew the data.

Pictures

  1. Peter Gugerell, Wien 01 Virgilkapelle a (inside the Virgil Chapel), 2013. Wikimedia Commons. Licence: CC0 1.0. Change: portrait crop, slow push.
  2. Peter Gugerell, Wien 01 Virgilkapelle b (niche of the Virgil Chapel with a wheel cross), 2013. Wikimedia Commons. Licence: CC0 1.0. Change: grows out of the drawn chapel in the film.
  3. Peter Gugerell, Wien 01 Stephansplatz a (west front of St. Stephen’s Cathedral), 2012. Wikimedia Commons. Licence: CC0 1.0. Change: crop of the facade, framed above the drawn cross-section.
  4. Adolph Menzel (painter), Der Esterházykeller in Wien, 1871. Österreichische Galerie Belvedere, via Wikimedia Commons. Licence: gemeinfrei (Public Domain). Change: framed, slow push.
  5. Leopold Senfelder (photographer), 1., Stephansplatz 1 - Stephansdom - Katakomben, around 1910. Wien Museum, inv. no. 34879/1. Licence: CC0 1.0. Change: photo only, without mount and colour chart; framed, slow push.
  6. H. Fritzmann (Skizze), Die Gartenlaube, In den Katakomben zu St. Stephan in Wien, 1872. Wikimedia Commons. Licence: gemeinfrei (Public Domain). Change: framed, slow push.
  7. UrLunkwill, Stephansplatz (the square from the cathedral tower, with the coloured outlines of the Magdalene and Virgil chapels in the paving (black lines since 2017)), 2008. Wikimedia Commons. Licence: CC BY 2.5. Change: framed crop, slow push.
  8. Jakob Hoefnagel, Virgilkapelle drawing (the Magdalene Chapel above the Virgil Chapel), 1609. Wikimedia Commons. Licence: gemeinfrei (Public Domain). Change: unchanged, framed.
  9. Yoichi Okamoto (photographer, US Environmental Protection Agency (DOCUMERICA)), St. Stephens Cathedral and subway construction on the street below, July 1973. National Archives (NARA 549680), via Wikimedia Commons. Licence: gemeinfrei (Public Domain). Change: black slide border removed, portrait crop, slow push.
  10. N. Levi, M. Weissl, K. Decker, Assessing the hazard of fault triggering by deep geothermal energy production in an active fault system via a 1D stress model and 3D fault mapping, Fig. 5 (strata of the Eßling Thermal 1 borehole (“Well 1”)), 2024. International Journal of Earth Sciences. Licence: CC BY 4.0. Change: redrawn as our own column with German labels (lake bed, sea floor, hot water, Alpine rock); the figure itself is not in the film.

AI, voice and music

Nothing in the film is painted with AI: the cross-section and the column are our own drawings based on the sources, schematic in width and position; the depths are documented. Voice and music are AI-generated: the voice with Gemini 3.8 Flash TTS (“Charon”), the music with Google Lyria 3 Pro via OpenRouter.

Evidence for the statements

How wohnwahn measures