Rebecca Morelle at the BBC:
In the 1960s, researchers unearthed two gigantic dinosaur arms. For decades, scientists have speculated about what kind of beast they belonged to.
Now, the rest of the dinosaur's body has been unearthed, and researchers say that the creature is even more bizarre than they had thought.
They say it was huge, with a beak, a humped back and giant, hoofed feet.
The study is published in the journal Nature.
Lead researcher Yuong-Nam Lee, from South Korea's Institute of Geoscience and Mineral Resources (Kigam), said: “It turned out to be one of the weirdest dinosaurs, it's weird beyond our imagination.”