Social Studies · Lesson · Class 5–9

The Himalayas and Sagarmatha (Mount Everest)

Q: How did the Himalayas form?

About 50 million years ago, the Indian tectonic plate collided with the Eurasian plate. Because both plates are continental and buoyant, neither sank; instead the crust crumpled upward into the great fold mountains we call the Himalayas. The collision continues today, pushing the range up a few millimetres per year.

Q: How tall is Mount Everest (Sagarmatha)?

8,848.86 metres. This official height was jointly announced by Nepal and China in December 2020, replacing the older 8,848 m figure used for decades.

Q: Why does Nepal have so many earthquakes?

Nepal sits directly on the boundary where the Indian plate is colliding with the Eurasian plate. The tremendous stress that builds up is released in earthquakes, like the devastating Gorkha sequence of April–May 2015. The Himalayas literally owe their existence — and their danger — to this same collision.

The Himalayas were born when the Indian plate slammed into the Eurasian plate about 50 million years ago — and they are still growing. Sagarmatha, known as Mount Everest in English, rises 8,848.86 metres above sea level on the Nepal–China border, making it the highest point on Earth.

Why the Himalayas exist

India was once a giant island floating on the Tethys Ocean. As the Indian tectonic plate drifted north, it collided with the Eurasian plate. Both are made of thick, buoyant continental crust, so instead of one sinking under the other, the land crumpled upward into mountains — just as a carpet on the floor rucks up when you push it.

Then vs now: 50 million years ago — a coastline near today's Nepal. Today — peaks over 8,000 metres high.

The collision continues: the Indian plate still moves north about 4–5 cm per year, and the Himalayas rise a few millimetres per year (while rivers and erosion wear them back down).

Length: the Himalayan range is roughly 2,400 km long, stretching through Pakistan, India, Nepal, Bhutan and China.

Nepal's geography — three steps from the sky to the plains

Mountain (Himal) region — high peaks above 4,000 m, permanent snow and ice, thin air. Sparse population; home to Sagarmatha National Park (a UNESCO World Heritage Site).
Hill (Pahad) region — 700–4,000 m, terraced farming, Pokhara and Kathmandu valleys, most of Nepal's cultural heartland.
Terai (Madhesh) region — flat plains below ~200 m, fertile farmland, dense population and the cross-border trade corridor with India.

Why the Himalayas matter — beyond the view

Water tower of Asia: the great rivers — Koshi, Narayani/Gandaki, Karnali — rise in the Himalayas. They feed hundreds of millions of people downstream, including all of the Ganges basin.

Climate wall: the range blocks cold air from Central Asia and helps drive the monsoon, giving Nepal its growing season.

Earthquakes: the same plate collision stores enormous stress. The Gorkha earthquake of 25 April 2015 (magnitude 7.8) killed nearly 9,000 people and injured over 22,000 — a reminder that this is a living, moving boundary.

Identity & economy: Sagarmatha is the tallest mountain on Earth, the flag symbol on Nepal's unique non-rectangular flag, and the magnet for mountain tourism that employs thousands of Nepalis.

Try it yourself

1. The Himalayas formed mainly because…

2. How tall is Sagarmatha (Mount Everest)?

3. Which region of Nepal is the flat, fertile southern belt?

Remember 3 things

Indian plate + Eurasian plate, ongoing collision ≈ 50 million years, still rising today.
Nepal = Mountain (Himal), Hill (Pahad), Terai — three geographical belts.
The Himalayas give us water, climate and identity — and also earthquakes; preparedness is survival.

Frequently asked questions

How did the Himalayas form?

About 50 million years ago the Indian plate collided with the Eurasian plate. Neither could sink, so the crust crumpled upward into the highest mountains on Earth — and it still rises a few millimetres per year.

How tall is Mount Everest (Sagarmatha)?

8,848.86 metres — the official height jointly announced by Nepal and China in December 2020.

Why does Nepal have so many earthquakes?

Nepal sits on the collision boundary itself. The stress that built the Himalayas is released in earthquakes, like the 2015 Gorkha earthquake.