Record: 700 km
The Eurasia Canal (Russian: Канал "Евразия", Kanal "Evraziya") is a proposed 700-kilometre-long (430 mi) canal connecting the Caspian Sea to the Black Sea along the Kuma-Manych Depression. Currently, a chain of lakes and reservoirs and the shallow irrigation Kuma-Manych Canal are found along this route. If completed the canal would also link several landlocked countries in Asia with the open seas through the Bosphorus.