The definition of a mountain in the US is a steep natural elevation above 300 m (1,000 ft), whereas in the UK the stipulation is above 600 m (2,000 ft).
The UN describes different categories of mountains ranging from 300 m to over 4,500 m, and suggests that mountains cover 27% of global terrain.
Everyone knows Mount Everest is the highest mountain on Earth at 8,850 m (29,035 ft) above sea level, but what about the tallest mountain? That record belongs to Mauna Kea in Hawaii, at 10,203 m (33,474 ft), though most of it is submerged in the Pacific.
What about the highest mountain in the known universe? Mars has Olympus Mons which measures a whopping 21,230 m (69,650 ft) and covers an area more than half the size of France.
Going by the UK definition, there have been films about whether a hill is a mountain, The Englishman Who Went Up a Hill But Came Down a Mountain, and a true story where life mirrors art, in the case of Snowdonia’s Mynydd Graig Goch.