Where would you be more likely to find a large city, on top of a high mountain or on a plain? why?

Large cities are more likely to find on a plain.

Explanation:

For a city to be established, geographical locations like vast plains, mountains, islands etc play a very important role. Cities are mostly established on the vast plains as compared to the other geographical locations.

Because of the facilities which the plains offer for the settling of the humans on that land like easy transportation leading to trade, setting up of businesses and growth. Taking up of agricultural activities also become easy in this plain land because use of equipment and machines become very easy.