The Hindu Kush Mountains form a barrier between the Indus River and present-day Afghanistan.

Although they are not as tall as the Himalayas they are still one of the world's tallest mountain ranges, with some peaks reaching 5 miles into the sky.

The Khyber Pass formed a gap around 30 miles long on the border of Pakistan and Afghanistan. For thousands of years, traders used the pass to enter the Indus River valley. Invaders also used the
pass, but some died in the harsh landscape.