This paper is based on experience in Iran where, with only twenty five million people in a land the size of Western Europe, space is not a problem. It is 3 200 km across its longest axis and nearly 2 400 km from north to south. It is one of the highest countries in the world, consisting mainly of a large plateau, 1 500–1 800 m above sea level, which is ringed by huge mountains running for the most part north-west to south-east except for the Elburz Chain running east to west and dividing the lush sub-tropical Caspian littoral from the arid plateau. In the centre, ringed by mountains, are two vast and confluent deserts, the salt and sand deserts, into which many rivers flow, all the time weakening and drying in the shimmering heat and dryness. The Zagros and Elburz ranges rise in places to 4 500 m and are snow covered for half the year.