Doughnutdelf is located beneath Stonehenge (citation needed). It is mostly a large and cavernous space with buildings constructed of rock and has a tea river (citationed needed BtL). Smaller caves exist and rooms carved into the walls of the cavern with balconies. One such room is located high up and belonged to Merlin[Pan 1].
Merlin's room is located high off the ground meaning only those capable of flight (or similar means) can reach it. It has a large yawning entrance with a balcony overlooking the city. Astrolabes and graphs and books would be cluttered on the floor and furniture with primitive-looking runes and cave drawings. Beakers and cauldrons filled with concoctions of many colours, and there was a rack full of nearly a dozen different mystical staves[Pan 1].
Pantheons of the NeSiverse
Once the centre of learning for mages, Doughnutdelf was the home of druids and Merlin the Wizard. Merlin had three apprentices - Lynne, Morganna le Fay and Nyneve the NeSferatu. Merlin ultimately chose to pass on the mantle of NeSorcerer to Nyneve, though Morganna believed it was because she was Merlin's lover. Once Nyneve possessed the NeSpell she betrayed Merlin and had her NeSferatu enter Doughnutdelf and slaughter most of the mages and druids there. She then trapped Merlin within its walls using a powerful spell of entrapment[Pan 1].