The Dutch Waterline is a historical defense system in the Netherlands designed to protect the country from invasions. It consists of a series of interconnected waterways, dikes, and flooded areas that could be quickly inundated to create barriers against enemy forces. This innovative strategy allowed the Dutch to use their natural landscape to their advantage. Originally established in the 17th century, the Waterline played a crucial role during conflicts, particularly in the Eighty Years' War against Spain. The system was effective in slowing down enemy troops and providing time for the Dutch military to organize a defense. Today, it is recognized as an important part of Dutch heritage and engineering.