Stories about a supposedly secret Russian craft called an "ekranoplan" are regularly featured on websites, blogs and online forums. Information about the craft also circulate via email, often with the following image attached The strange-looking craft might seem like something from science fiction, but ekranoplans are real and the photograph is genuine. Although they may resemble aircraft, ekranoplans are in fact ground-effect vehicles that fly a few feet above any flat surface. Very basically, air compressed under a wing moving near the surface provides lift to the craft.
The ekranoplan in the photograph is a Soviet vehicle seen on the Caspian Sea during the 1960's. An article about the craft on The Register notes:
During the mid-1960s chilly height of the Cold War, US photo reconnaisance spotted a strange apparition on the shores of the Caspian Sea - a gigantic 100m-long aircraft with inexplicably truncated square wings. US Intelligence dubbed the beast the "Caspian Sea Monster", unaware that the Russians were developing not, as they thought, an enormous conventional seaplane, but rather a 550-ton water-hugging behemoth designed to use the ground effect to skim the ocean at high speed, undetected by radar.
The Russians are not the only ones to built such craft. Others have continued to develop them to this day.
For an in depth analysis and history of ekranoplans, see:
In search of the Caspian Sea Monster
Other ekranoplan resources:
Wikipedia: Ekranoplan
YouTube video of an Ekranoplan