The first satellite photos of this vehicle, as it sat inland, were taken by an American spy satellite and it was believed to be a normal Jumbo-jet-size aircraft. But questions were flying:
"Why is a huge jumbo jet sized plane sitting in water? "
Well, the strange vessel was the Caspian Sean Monster, officially KM (Korabl Maket or "prototype ship" in Russian). It was an experimental 544-ton ekranoplan (ground effect vehicle) designed by Rostislav Evgenievich Alexeev in the period 1964-1965. It was manufactured in Central Hydrofoil Design Bureau with lead engineer of the project V.Efimov.
The KM was a special vehicle designed for military and rescue teams. It was documented as a marine vessel but piloted by test pilots from the air force. Its first flight was on October 16, 1966. KM was designed to reach operational speed of 270 knots and maximum – 350 knot (650 km/h).
The vessel sunk in 1980 after an error by its pilot. The incident caused no casualties.