The UK Geoenergy Observatory in Glasgow has released data and images from up to 199 metres below the surface of the city.
The data will help scientists understand the subsurface better and shed light on how mine water heat could be used as a renewable energy source for homes and industry.
It is taken from the Glasgow observatory's 12 boreholes, which range from 16-199 m deep and are fitted with 319 state-of-the art sensors.
The network of boreholes is observing how warm water moves abandoned, flooded mine workings beneath the east end of the city and Rutherglen.
Over the next 15 years, the boreholes will allow scientists to monitor changes in the chemistry and to the physical and microbiological properties of the environment below the surface.
The new data includes drilling logs, hydrogeological test data and optical images taken underground. The data is open for scientists to use, and the Observatory team hope that researchers from around the world will get in touch to use the boreholes.
Dr Alison Monaghan, science lead for the UK Geoenergy Observatories, Glasgow, said: "The Glasgow Observatory's boreholes are giving us an unprecedented look into the subsurface.
"Data from underneath Glasgow can now be used by scientists around the world to close the knowledge gaps we have on mine water heat energy and heat storage.
"Mine water heat is one form of geothermal energy, and it has huge potential to help the UK decarbonise its heat supply and meet net zero targets.
"There are many cities and towns in the UK that are sitting on top of old mine workings, particularly in central Scotland, northern England and south Wales.
"While this data is from Glasgow, it will help researchers around the world better understand the subsurface.
The UK Geoenergy Observatories are a £31 million investment by the UK government through UK Research and Innovation (UKRI) and the Natural Environment Research Council (NERC).
The Glasgow observatory is one of two new facilities to be built as part of the project. Construction will soon begin on a second observatory in Cheshire, which covers a range of geoenergy technologies including shallow geothermal and heat storage. An existing urban geo-observatory in Cardiff provides data on shallow geothermal heat recovery and storage.
Over the next 15 years, the boreholes at the Glasgow Observatory will continue to produce data that sheds light on what's happening below the surface, providing environmental baselines and critical information for scientists.
Dr Monaghan said: "Our next data releases will include hydrogeological pump test results, groundwater chemistry and infrastructure available at each borehole site."
The data is contained in information packs, which are now available.
