Rarely seen : photographs of the extraordinary

Boasting a major cool factor, the latest entry in National Geographic's iconic line of large-format photography books reveals some of the world's most astounding phenomena - from the desert flower that only blooms once a year to a priceless Egyptian artifact buried for years in King Tut's tomb.It's all here: 30,000-year-old cave art sealed from the public; animals that are among the last of their species on Earth; volcanic lightning; giant crystals that have grown to more than 50 tons; the engraving inside Abraham Lincoln's pocket watch.