We all know about Edinburgh's landmark attractions; we've got the castle, we've got Arthurs Seat, we've got Holyrood House.
What a lot of tourists, and locals, don't know about - is what's lurking underneath our streets.
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In Gilmerton, an underground set of hand carved tunnels lay under the suburb, thought to date back to the 18th century.
While the origins remain a mystery, there are rumours the caves were used as a drinking den.
An ex-mining village, Gilmerton now sits right on the edge of the city four miles from the centre.
While the Gilmerton Cove is thought to have been there for centuries, it wasn't until 2003 that the newly restored cave was opened to the public.
The City of Edinburgh Council collaborated with Gilmerton Heritage Trust to open the cove as an educational resource for the community, as well as a visitors attraction.
Despite this renovation, little is known about the roots of Gilmerton Cave after extensive archaeological and historical research.
Scientists from the University of St Andrews and the University of Edinburgh did discover in 2017 that the network of passageways may in fact be far more extensive than currently exposed.
When excavators initially discovered the underground rooms in 2002, they found seven subterranean rooms that were thought to be untouched for over 200 years.
Whoever was behind the cove carved out tables, separate rooms and doorways - making an almost liveable space.
In one section, a circular hole in one of the ‘tables’ is thought to have been a punch bowl, which alludes to the theory that Gilmerton Cove was a drinking den.
The cove, which is built around a main corridor that stretches over forty feet, has two separate entrances carved from natural sandstone.
Also connected via a secret passage, was the nearby Hellfire Club.
The Hellfire Clubs were a nationwide association of high society members who engaged in ‘immoral activities’ and mocked religion, dining on ‘Holy Ghost Pie’ and ‘Devil’s Loin.’
Another contributing factor to the theory that Gilmerton Cove was an underground boozer comes from George Paterson.
George was an 18th century local blacksmith, who is thought to have lived in the cove between 1719 and 1724.
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Parish records from the time show he was reprimanded for allowing alcohol to be consumed in the cove on the Sabbath, though it is not known if George carved the cove himself.
In 1897, an Assistant Keeper at the National Museum of Antiquities in Edinburgh made a detailed study of the caves.
He reported that it was unlikely that one man could have carried out the work in only a few years, and concluded that the Gilmerton Cove went back much further than the 18th century.
Aside from being the Gilmerton local drinking hole, another popular theory argues that it could have been used to house Covenanters in the 17th century.
Covenanters were those who supported the Presbyterian Church of Scotland, and were part of a religious movement following disputes with King James I.
The Covenanters took control of Scotland after the Bishop Wars, pushing against changes imposed on the kirk.
They became a persecuted minority after the 1660 Restoration, with death penalties and torture imposed for any Covenanters preaching in public - and many held services in hidden places to avoid persecution.
The cove’s use as a hiding place also comes into play in another theory, which argues the tunnels were made in the 16th century at the time of the Battle of Flodden.
After King James VI and his army were destroyed by the English at the Battle of Flodden, many felt another invasion was imminent.
It’s possible that locals created a hideaway to stay safe from invasion.
Other theories behind the the passageways include it being a Witches Coven and a Knights Templar Retreat.
Any and all of the speculations surrounding Gilmerton Cove’s past could be true, though it’s likely we’ll never know for sure.
You can check out the chambers for yourself, find out more on the Gilmerton Cove website.
