To stay in which ground is the major part of Hajj?

To stay in which ground is the major part of Hajj?

حج کا بڑا حصہ کس میدان میں ٹھہرنا ہے؟
Explanation

It is an important place in Islam because, during the Hajj, pilgrims spend the afternoon there on the ninth day of Dhu al-Hijjah.

Failure to be present in the plain of Arafat on the required day invalidates the pilgrimage.