The Brewery Guilden im Zims is located partially on historical Mauwerk from the Roman period , seven meters below the level of today's Heumarkt. The exposed walls, with wall thicknesses up to 1.80 meters and different masonry combined , consist of mostly basalt , fired bricks and granite . Partly still active wells have been restored in the course of extensive remodeling measures in 2006 to 2009. The house is a station of Cologne's historic brewery trail. As a branch of the Cologne Carnival Museum , the building houses a carnival permanent exhibition