On 28 May 1932, at exactly 13:02, a small amount of clay sealed the final gap in a 32-kilometer-long dike, effectively closing the Zuiderzee—a saltwater inlet connected to the North Sea for centuries. This barrier, known as the Afsluitdijk (or "closing dike"), transformed the saltwater gulf into a freshwater lake named IJsselmeer. The dike serves as both a major dam and a road in the Netherlands, where water levels differ on either side. Lock systems at both ends allow boats to pass through, facilitating transportation and trade. The idea for the Afsluitdijk originated in 1891 with young engineer Cornelis Lely, who later had the project included in the national government agenda in 1913. After the devastating 1916 flood, which submerged large parts of the Dutch coast and exposed the inadequacy of existing dikes, the project became a national priority. Once completed, the dike reaches up to 7.25 meters above sea level and has repeatedly proven its protective value, saving countless lives from potential floods. Closing the Zuiderzee was only the beginning of a larger transformation. Over the following decades, Dutch engineers drained large sections of the seabed, creating new land through a process known as poldering. The Wieringermeerpolder, covering 20,000 hectares, was drained in 1932, followed by the Noordoostpolder (48,000 hectares) in 1942. The Eastern Flevoland (54,000 hectares) was completed in 1957, with agricultural development continuing into the 1970s. The Southern Flevoland emerged in 1968 and is notable for being completely surrounded by water—a technique used to prevent subsidence in surrounding areas. This made Flevoland the world's largest artificial polder island. A fourth polder, which would have drained part of the neighboring Markermeer, was planned but never completed due to post-war economic constraints, leaving the Markermeer as the last remaining body of water from the original vision. Flevoland, a province entirely created from water, was officially established in 1986, nearly half a century after the Afsluitdijk was completed. It was formed by merging two polders: the Flevopolder (which includes South and East Flevoland) and the Noordoostpolder, drained from the former Zuiderzee. The province is geologically young, with an average elevation of less than 5 meters and a maximum of under 14 meters, covering 1,411.63 square kilometers. Today, it is home to 423,000 people, or about 299 per square kilometer, with Lelystad, a city of 60,000, as its capital. This population now lives on land that was once the ocean floor. The only natural remnants are a few hills that were once islands, like Urk, a former island that is now surrounded by farmland. A village that once relied on fishing now finds itself in a landscape of wheat fields, without moving a single meter. Scientists continue to debate the long-term implications of this transformation. The closure of the Zuiderzee had more than just geographic consequences. It disrupted ecological balances that had taken centuries to develop. Researchers remain divided on the extent of these changes. The dike closure in 1932 abruptly stopped centuries of fish migration between the North Sea and the freshwater lake. To address this, the Vismigratierivier (Fish Migration River) was constructed, with its completion in 2023. Its full benefits are expected to be realized by 2027, when salmon and eels may begin to migrate freely again. Meanwhile, agricultural conditions in areas like the Noordoostpolder face challenges. The permeability of the sandy soil near the former coastline has intensified the need for water pumping, affecting groundwater levels and making farming more difficult. A century after the Afsluitdijk was completed, the Netherlands continues to reflect on the achievements and challenges of creating Europe’s youngest province.