This story originally appeared in Business Insider.

The relationship between the U.S. and Russia is more tense than it’s been since the collapse of the Soviet Union in the early 1990s. American and E.U. sanctions on the Russian government in the wake of Moscow-backed separatists’ destruction of a Malaysia Airlines passenger jet has Russian President Vladimir Putin backed into a corner — which, as the New Republic’s Julia Ioffe argues, is when he’s most dangerous.

But this isn’t the Cold War. There’s little actual danger of the Russians attempting to militarily threaten western Europe. Putin’s options are dwindling. He’s almost certainly more contained—strategically and militarily—than his Soviet predecessors, who had a trans-continental empire and some of the most incredible military technology of the time at their disposal.

The Lun-class Soviet Ekranoplane is one reminder of the stakes of the Cold War, and the capabilities of the communist bloc. A super-vehicle seemingly purpose-built for a major war with the NATO states, it’s a sign of how different Europe, Russia, and the world in general were just a relatively short time ago.

The Ekranoplane was a marvel of late 20th century technological prowess and the Soviets considered it an integral part of their colossal military machine.

Equipped with nuclear warheads and capable of blasting across the sea at 340 miles per hour, the Lun-class Ekranoplane was part plane, part boat, and part hovercraft. It took advantage of an aeronautical effect that allowed it to lift off with an immense amount of weight, but limited its flight to 16 feet above the waves—its altitude could never be greater than its wingspan.

Think of a large seabird, like a pelican, cruising inches from the water and not needing to flap its wings—but loaded with soldiers, missiles, and even nukes.

Only one of these extraordinary war machines was ever built. The only complete Ekranoplane now sits on the shores of the Caspian Sea, rusting away.

Business Insider’s Robert Johnson stumbled upon these pictures back in January of 2012, when aviation blogger Igor113 posted them to Live Journal.

The Lun-class Ekranoplane was used by the Soviet Navy starting in 1987, and wasn’t retired until the late 1990s, after the Soviet Union’s fall

At nearly 243 feet long—and at almost the size of the Spruce Goose—the Lun is a ground-effect aircraft that can only fly near the surface of the sea

Eight turbofans producing 28,600 pounds of thrust apiece are mounted at the nose of the vehicle

It has a “flying boat”-style hull and a “step” for takeoff

It was built for anti-surface warfare in the event of a European invasion or an unexpected attack from NATO forces

The vessel carried six P-270 Moskit guided missiles—armed with nuclear warheads

The missiles were mounted in pairs on the top of the vehicle’s hull

Its nose and tail concealed the most cutting-edge tracking systems and radar of the day

Another version of the Lun was slated to be a highly-mobile, fast-moving field hospital

… but funding for the medical version never materialized, and the plane was never built.

In 2007, Russia’s defense minister announced that the country would resume production of this model of Ekranoplane

The “wing-in-ground” effect allows the fully-loaded 2 million pound aircraft to fly low over the water — and even get decent fuel economy for a vehicle of its massive size

It was the first hovercraft to use turbojet power, and the first vehicle of its type to be operated successfully

The Lun could only fly at incredibly low altitude, and could not travel any higher than the length of its wings

The Lun could carry 15 officers, flying 340 mph and reaching a maximum operational range of 1,240 miles. It could only ever reach an altitude of 16 feet.

The effect that allows the huge Ekranoplane to skim the surface of the water can be seen in low-flying seabirds that glide above the sea without needing to flap their wings

These kinds of “Ground Effect Vehicles” are twice as efficient as traditional airplanes and can carry twice as much weight

The Lun also had an anti-submarine function, with six anti-ship missile launchers across the top of the fuselage

The Ekranoplane can carry hundreds of tons of cargo and troops, in addition to anti-ship and anti-submarine munitions and nuclear arms. A fleet of them would have allowed for a potential European invasion

The Lun isn’t perfect though. It risks tipping over if it banks sharply. And it can only take off into the wind

Though it has a tail gunner, the low-flying Lun would likely require fighter support as well

Though it can avoid mines and torpedoes, the hulking vehicle is vulnerable from the air

This is the only existing complete Lun. As of early 2012, it sat in Kaspiysk, Russia on the coast of the Caspian Sea.

See Also: A Russian Soldier’s Instagram in Ukraine