Arthur and Gwen's ChambersEditArthur's room has been shown in many of the episodes in the Merlin series. This is Prince Arthur's personal chamber. When Gaius got possessed by a Goblin, Arthur had a lot of gold coins which the Goblin (trapped in Gaius' body) stole. He had won the money in a competition. Arthur later married Gwen and they shared this room as seen in The Dark Tower.
Uther's Chambers bear a resemblance to Arthur's Chambers. Gwen was revealed to be looking after him during the events of Series 4 (The Darkest Hour). Uther's chambers have appeared in several episodes of first four series but haven't been seen since the death of Uther (The Wicked Day). Uther briefly shared his room with his troll wife when they were married
Morgana's ChambersEditMorgana's Chamber was the room occupied by the Lady Morgana from a young age until the end of season 3. The chambers were seen again in season 4, redressed as Agravaine's chambers. However it is unknown if Agravaine was living in Morgana's old chambers or in a different room that looked similar. For some reason Morgana did not move back into her chambers after her second conquest of Camelot instead moving into Arthur's chambers. The chambers included Morgana's wardrobe.
Burial VaultEditA vault beneath Camelot Castle houses a number of sarcophagi, each containing the remains of a deceased noble.
It is almost certain that the remains of Ygraine de Bois reside in this burial vault as well.
Morgana used the Rowan Staff from the Rowan Tree on the Isle of the Blessed to resurrect an army of the dead during the Great Battle for Camelot. Merlin intervened and they duelled in this place. Morgana defeated Merlin but Merlin secretly used magic to take down Morgana and destroyed the Rowan Staff, which made the undead army perish (The Tears of Uther Pendragon). It is presumed that Uther was burned here as well after his death. He may be laid next to his beloved wife, Ygraine.
Water VaultEditA vault beneath the Castle of Camelot contained a large storage unit that supplied the city with drinking water. The vault appeared to be accessible only through a single locked door that lead into a downward stone staircase and into an expansive cavern system. It is currently unknown if the water vault connected to the Dragon's cave or to the burial vault that also resided below Camelot.
The year that Merlin arrived in Camelot to begin his apprenticeship with Gaius, the sorceress Nimueh magically transported the egg of an Afanc into Camelot's water supply, releasing a deadly plague into the city. After Gaius and Merlin deduced that the pathogen was spread through the water, they descended into the vault and discovered the Afanc. Merlin later returned to the vault with Arthur Pendragon and Morgana, and aided Arthur in the destruction of the creature (The Mark of Nimueh).