The Ponttor is one of the two remaining gates of the original city wall of Aachen. It was built in the 14th century and manned by soldiers and militia throughout the Free Imperial City of Aachen era. Today, the Ponttor is used by German Youth and Scout groups.
The Ponttor was constructed as a right-angled three-stock tower castle. In the main entrance, there is a Portcullis as well as a machicolation, through which things could be dropped on invading forces. A bridge passage with crenelations spanned a moat and was strengthened in the foregate with two reinforced towers (barbicans). The building material was Devonian sandstone, Pennsylvanian carbonite sandstone and quartzite, with the framing material made of light bluestone.
References:The Château du Lude is one of the many great châteaux of the Loire Valley in France. Le Lude is the most northerly château of the Loire Valley and one of the last important historic castles in France, still inhabited by the same family for the last 260 years. The château is testimony to four centuries of French architecture, as a stronghold transformed into an elegant house during the Renaissance and the 18th century. The monument is located in the valley of Le Loir. Its gardens have evolved throughout the centuries.