There is nothing new under the sun, they say. That is only relatively true. Just now, when we thought there was practically no portion of the earth's surface still unknown, when the discovery of a single lake or mountain, or the charting of a remote strip of coast line was enough to give a man fame as an explorer, one member of the daredevil explorers' craft has "struck it rich." Struck it so dazzlingly rich, indeed, that all his confrères may be pardoned if they gnash their teeth in chagrin and turn green with envy. The lucky man is Prof. Hiram Bingham of Yale, he whose hobby is South America. He has just announced that he has had the superb good fortune to discover an entire city, two thousand years old, a place of splendid palaces and temples and grim encircling walls, hidden away so thoroughly on the top of a well-nigh inaccessible mountain peak of the Peruvian Andes that the Spanish invaders of four hundred years ago never set eyes upon it. He calls it Machu Picchu.