Mount Everest is the Earth's highest mountain, with a peak at 8,848 metres (29,029 ft) above sea level. It is located in the Mahalangur section of the Himalayas. The international border between China and Nepal runs across the precise summit point.[citation needed] Its massif includes neighboring peaks Lhotse, 8,516 m (27,940 ft); Nuptse, 7,855 m (25,771 ft); and Changtse, 7,580 m (24,870 ft).
Nonetheless, in 1847, the British pressed on and began detailed observations of the Himalayan peaks from observation stations up to 240 km (150 mi) away. Weather restricted work to the last three months of the year. In November 1847, Andrew Waugh, the British Surveyor General of India made several observations from Sawajpore station located in the eastern end of the Himalayas. Kangchenjunga was then considered the highest peak in the world, and with interest he noted a peak beyond it, some 230 km (140 mi) away. John Armstrong, one of Waugh's officials, also saw the peak from a location farther west and called it peak 'b'. Waugh would later write that the observations indicated that peak 'b' was higher than Kangchenjunga, but given the great distance of the observations, closer observations were required for verification. The following year, Waugh sent a survey official back to Terai to make closer observations of peak 'b', but clouds thwarted all attempts.
