The Himalayan mountains were formed by the collision of two tectonic plates:

* The Indian Plate: This is a continental plate that was originally located much further south.

* The Eurasian Plate: This is another continental plate that covers much of Europe and Asia.

Here's how it happened:

1. Continental Drift: Millions of years ago, the Indian Plate was drifting northward.

2. Collision: Eventually, the Indian Plate collided with the Eurasian Plate.

3. Subduction: The Indian Plate, being denser, began to slide under the Eurasian Plate.

4. Uplift: The immense pressure from the collision caused the Eurasian Plate to buckle and fold upwards, creating the towering Himalayan mountain range.

This process continues today, causing the Himalayan mountains to grow taller by a few millimeters each year.