Before Mt. Everest was discovered as the highest mountain in the world, which mountain was the highest?

Why this works

This riddle plays on the concept of discovery and perception. Before Mt. Everest was officially recognized as the highest mountain, it still existed and was indeed the tallest, regardless of whether anyone had discovered it or not. The trick lies in the assumption that something's status can change based on human recognition, but in reality, Mt. Everest has always been the highest mountain, even before it was known to be so!