Boppard’s most famous sight is a castrum, a Roman Fort. The military camp of Bodobrica was established here in 360 AD. It is thought to be the best preserved example north of the Alps today. It once had 28 towers, and was a commercial centre as well as a fort. It was 308 × 154 metres and formed a rectangle of 4,7 hectare. The walls were 3 metres thick to the land side and 2,5 metres thick to the Rhine side. With a height of 9 metres and 20 horse-shoe shaped towers to the land side, each 27 metres apart, the wall made a very powerful fortification.
The fort can be wandered around freely and it is in remarkably preserved condition. Many of the finds that have been recovered and excavated from the site can be found in the Boppard museum.References:
Ängsö Castle was first named as "Engsev" in a royal charter by king Canute I of Sweden (r. 1167-1196), in which he stated that he had inherited the property after his father Eric IX of Sweden. Until 1272, it was owned by the Riseberga Abbey, and then taken over by Gregers Birgersson.
From 1475 until 1710, it was owned by the Sparre family. The current castle was built as a fortress by riksråd Bengt Fadersson Sparre in the 1480s. In 1522, Ängsö Castle was taken after a siege by king Gustav Vasa, since its owner, Fadersson's son Knut Bengtsson, sided with Christian II of Denmark. However, in 1538 it was given by the king to Bengtsson's daughter Hillevi Knutsdotter, who was married to Arvid Trolle.
In 1710, the castle was taken over by Carl Piper and Christina Piper. Ängsö Castle was owned by the Piper family from 1710 until 1971, and is now owned by the Westmanna foundation. The castle building itself was made into a museum in 1959 and was made a listed building in 1965. It is currently opened to visitors during the summers.
The castle is a cubical building in four stores made by stone and bricks. The lower parts is preserved from the middle ages. It was redecorated and expanded in the 1630s. The 4th storey as well as the roof is from the expansion of Carl Hårleman from 1740-41. It gained its current appearance in the 1740s.