Edinburgh had catacombs.
Whilst visiting the catacombs, Heather McCrimmon became separated from her friends after she witnessed a temporal echo of Great-Great-Great Grandmother McCrimmon being chased by the Mozhtratta. The Tenth Doctor found Heather shortly afterwards and explained what she had witnessed.
The Doctor determined that he needed Heather's help to deal with the Mozhtratta. He took her to his TARDIS - which was parked in the catacombs - and together they travelled to the Edinburgh High Street in 1815. (COMIC: The Chromosome Connection)