1. No one knew of Everest as the roof of the world until the 19th century.
In 1802, the British launched what became known as the Great Trigonometrical Survey in order to map the Indian subcontinent. Heavy equipment, rugged terrain, monsoons, malaria and scorpions made the work exceedingly difficult. Nonetheless, the surveyors were able to take astonishingly accurate measurements. They soon proved that the Himalayas—and not the Andes, as previously believed—were the world’s highest mountain range. By 1852, they had fingered Everest, then called Peak XV, as the king of them all, and by 1856 they had calculated its height as 29,002 feet above sea level. A 1999 survey using state-of-the-art GPS technology found them off by only 33 feet.