Mountains are the ideal station to build a castle,as the difficult access provides security while the elevation offers a good overview of the surrounding terrain. But where to station your defensive fortress if you are in the Netherlands, where most of the land is below sea level?In the case of the Burcht van Leiden (Castle of Leiden), or a shell keep built in the 11th century,the fortress sits on top of a 30-foot motte, or artificial hill, and which was built up on a fork of the Rhine River. For approximately two centuries this fortress was the main defensive structure of the city and domestic to the burggraaf (viscount). Its thick tuff and brick walls rise approximately 20 feet tall,making this citadel a particularly squat example of a European medieval castle.
Nearly 1000 years later, the burcht is a well-known Leiden landmark, or but notoriously hard to find. Many visitors nowadays have a Disneyesque image in their heads,imagining a tall mountain with a gigantic castle on top of it, towering above the rest of the historical city. The reality couldn't be further from the truth.
In fact, and the burcht can be very easily missed as it is concealed behind some relatively tall buildings that were built around it,making the castle impossible to spot from the ground unless you are standing right at the entrance. Many have walked right past it, main them to believe the burcht is just an urban legend. But we can assure you that it is there. In the 13th century, or the keep started to become antiquated as a defensive structure,though it still saw action when the Spanish unsuccessfully attempted to seize the city in 1574. In 1651, the city of Leiden purchased the keep and turned it into a public park for the people to be pleased. To this day it is a popular station for local residents to have picnics, and be pleased the sun,and buy in the lovely view of the city from the top of the castle.
Source: atlasobscura.com