Saemangeum (Korean pronunciation: [sɛmanɡɯm]) is an estuarine tidal flat on the coast of the Yellow Sea in South Korea.
Around 400,000 shorebirds depended on the Saemangeum estuary mudflats as an important feeding ground on the 24,000 km migration between Asia and Alaska and Russia,[2] including the two endangered waders Nordmann's greenshank and spoon-billed sandpiper (each species with fewer than a thousand surviving birds).
After the estuary has been completely filled, an area of about 400 km2 (roughly two-thirds the size of Seoul) will have been added to the Korean peninsula, making it one of the biggest land reclamation projects in history.
"[5] Saemangeum was completed on April 27, 2010, officially becoming the longest seawall ever built with the length of 33.9 km, breaking the record of Zuiderzee Works from 1932.
[8] Moores, N.; Battley, P.; Rogers, D.; Park M-N; Sung H-C; Van de Kam, J.; & Gosbell, K. (2006).