Photo of Mt. Everest from the International Space Station
Mount Everest is the planet earth's highest mountain, with a peak at 8,848 metres (29,029 ft) above sea level.
Fun fact: Olympus Mons is the highest mountain in the solar system -- it's on Mars.
Mount Everest is part of the Himilayan mountain range which runs across northern India causing a natural border between India and China (the smaller countries of Nepal and Bhutan are both part of the mountain range).
Mount Everest is partially in Nepal and partially in China (Tibet)... The international border between China and Nepal runs across the very top of the mountain. The top of a mountain is called the summit.
Tibet was an independent country at one time, but at the moment, China holds it. The north side of Mount Everest is in Tibet.
The south side of Mount Everest is in Nepal. Nepal is a "sovereign nation" which is a fancy way of saying it is a country that rules itself. It was a monarchy up until the 1990's at which point it became a parliamentary monarchy. In a monarchy, the country is ruled by Kings and Queens, usually all from the same family. In a parliamentary monarchy, the country still has kings and queens but it also has elected representatives and a Prime Minister. This is the type of government Great Britain has too.
Sir Edmund Percival Hillary was a New Zealand mountaineer and explorer. On May 29, 1953 at the age of 33, he and sherpa Tenzing Norgay from Nepal became the first climbers known to have reached the summit of Mount Everest.
Queen Elizabeth, II was coronated on June 2, 1953. "Being coronated" means receiving her crown and becoming the queen. She found out about Hillary's accomplishment during her coronation and decided to make him a knight. That's why he's called Sir Hillary.
Hillary and Tenzing are also nationally recognized in Nepal, where ceremonies are held every year on May 29th to celebrate their accomplishment.