Here's why:

* Convergent boundaries occur when two tectonic plates collide.

* Continental-continental collisions happen when two landmasses push against each other. Since both landmasses have similar densities, neither can subduct (slide) under the other.

* The Himalayas are formed because the Indian Plate, a continental plate, collided with the Eurasian Plate, another continental plate. This collision caused the land to buckle, fold, and uplift, resulting in the formation of the Himalayas.

It's important to note that while the Himalayas are formed by a continental-continental convergent boundary, there are other types of convergent boundaries as well, such as oceanic-oceanic and oceanic-continental.