The lower level in Kaer Morhen in The Witcher 3: Wild Hunt.
Seen in the Tutorial Quest.
Geralt comes down here, after taking a bath in the Bedroom. A Spiral stairway leads here from the bedroom.
Vesemir fell asleep while Ciri was reading a book about Ghouls. When Vesemir woke up, Ciri was gone. She went down to the Battlements to train in fighting.
Geralt speaks to Vesemir to discuss Ciri's training
They watch Ciri training on the Battlements and then Geralt goes there to talk to her.