The highest point on land is the top of Mt. Everest (in the Himalayas on the NepalTibet border) at 29,035 feet [8,850 meters]) above sea level. This measurement, taken using satellite-based technology, includes the snow and ice layers which are estimated at between 30 feet (9 meters) to 60 feet (18 meters). The National Geographic Society accepted this height in November 1999. The U.S. National Imagery and Mapping Agency has also accepted 29,035 feet (8,850 meters) as the official height. There is hope that ground penetrating radar will one day be used to determine the snow pack depth. The height established by the Surveyor General of India in 1954 and accepted by the National Geographic Society was 29,028 feet (8,845 meters) plus or minus 10 feet (three meters) because of snow. Earlier measurements indicated the height of Mt. Everest was 29,002 feet (8,840 meters). Satellite measurements taken in 1987 indicated that Mt. Everest is 29,864 feet (9,102 meters) high, but this measurement was not adopted by the National Geographic Society.

The lowest point on land is the Dead Sea between Israel and Jordan, which is 1,312 feet (399 meters) below sea level. The lowest point on Earth’s surface is thought to be in the Mariana Trench in the western Pacific Ocean, extending from southeast of Guam to northwest of the Mariana Islands. It has been measured as 36,198 feet (11,034 meters) below sea level.