The Kazemat van Fort de Liede is a part of the defence line which was built at the end of the 19th century in order to protect Amsterdam from attack. The line used a combination of canals, locks, and forts, to direct water away from certain parts of the town in times of peace, and enable the same areas to be quickly flooded during times of war. The defence line took around 30 years to build, and extended over 130KM around the city. Many parts of the line are still intact, and are now UNESCO protected monuments.
