King's cellars
The king's cellars were the lowest levels of Thranduil's halls.
Description
At the lowest part of the caves were the cellars of the king. These cellars were built over an underground stream so that empty barrels could be dropped into the water and flowed through a rough tunnel and out into the Forest River through a water-gate barred by a portcullis.
History
In the autumn of TA 2941, Thorin and Company were traversing Mirkwood and were captured and brought to Thranduil's halls. Bilbo Baggins, however, roamed invisibly, wearing the One Ring, about the halls and discovered the king's cellars by lurking behind a large barrel. He learned by listening to the king's servants how empty wine-barrels were often thrust through the great oaken trap doors and the water-gate.
By luck, that evening, the chief of the guards was tempted by the king's butler to try out some potent wine. As a consequence, Bilbo was able to obtain the keys to the Dwarves' cells in the king's dungeon. He managed to free them all and pack them into empty wine-barrels in the cellars. Some Wood-elves returned from the king's feast and, after waking the butler, rolled the barrels out through the trap doors.