Here's why:

* Formation: They are still actively forming due to the ongoing collision of the Indian and Eurasian tectonic plates.

* Age: They are estimated to be around 50 million years old, making them significantly younger than other major mountain ranges like the Appalachians (over 400 million years old).

* Height: The Himalayas are home to some of the world's highest peaks, including Mount Everest, which continues to grow slightly due to the ongoing tectonic pressure.

Other young fold mountains include the Alps and the Andes, but the Himalayas are generally considered the youngest due to their ongoing formation and dynamic nature.