In the cellars, accessed from street level under Lejonbacken, of the northern and western row is the Tre Kronor Museum. The museum is in the rooms that used to be kitchens in the Tre Kronor Castle and are thus the oldest rooms in the Palace, but the museum itself is the newest of the museums in the palace. It was inaugurated in 1999, and houses an exhibition about the old castle Tre Kronor which was destroyed during a fire in 1697.