The Alps are relatively young mountains, geologically speaking. They formed during the Cenozoic Era, specifically the Miocene and Pliocene epochs, which began around 23 million years ago and continued until 2.6 million years ago.

However, the story of the Alps is more complex than just their age. They are the result of a long and ongoing process of mountain building (orogeny) caused by the collision of the African and Eurasian tectonic plates. This process continues today, albeit at a much slower rate than in the past.

So, while the Alps themselves are roughly 23-2.6 million years old, the geological processes that created them have been happening for far longer, stretching back hundreds of millions of years.