It’s on Mars.
The giant volcano Mount Olympus – or Olympus Mons in Latin – is the highest mountain in the
solar system and in the known universe.
At 22 km high (14 miles) and 624 km (388 miles) across, it is almost three times the height of
Mount Everest and so wide that its base would cover Arizona, or the whole of the area of the British
Isles. The crater on the top is around 72 km (45 miles) wide and over 3 km (nearly 2 miles) deep,
easily big enough to swallow London.
Mons Olympus doesn’t conform to most people’s idea of a mountain. It is flat-topped – like a vast
plateau in a sea drained of water – and its sides aren’t even steep. Their slight incline of between one
and three degrees means you wouldn’t even break sweat if you climbed it.
We traditionally measure mountains by their height. If we measured them by their size, it would be
meaningless to isolate one mountain in a range from the rest. That being so, Mount Everest would
dwarf Olympus Mons. It is part of the gigantic Himalaya–Karakoram–Hindu-Kush–Pamir range
which is nearly 2,400 km (1,500 miles) long.