Here's why:

* Continental-continental collisions involve two continental plates pushing against each other. Both plates have similar densities, so neither plate can subduct under the other.

* Intense Uplift: This results in intense pressure, causing the crust to buckle, fold, and uplift, forming massive mountain ranges.

* Example: The Himalayas, the highest mountain range on Earth, are a prime example of mountains formed by a continental-continental collision between the Indian and Eurasian plates.

Other types of plate collisions:

* Oceanic-oceanic collisions: These collisions create island arcs, like Japan, as one oceanic plate subducts under another.

* Oceanic-continental collisions: These collisions result in volcanic mountain ranges along the coast, like the Andes Mountains.

While other collisions create mountains, the massive scale and sheer size of mountains formed by continental-continental collisions make them the most extensive.