US vs Iran
Iran is peppered with mountains. The country enjoys several natural defences: the Alborz mountain range in the north and the Zagros mountain range in the west and part of the south. The Alborz mountain range stretches from the borders of Armenia in the north-west to the southern end of the Caspian Sea, (Iran's highest peak, Damavand 5604m) and ending in the east at the borders of Turkmenistan and Afghanistan.
The Zagros Mountains (home to many Iranian military bases) are parallel ranges of folded mountains, almost impassable when travelling east-west, that run some 1700 km, beginning near the Turkish border, southeast along the western border of Iran down to the Strait of Hormuz at the very end of the Persian Gulf. The Zagros Mountains have numerous peaks higher that 3000 m. Snow is common throughout the ranges in winter and some higher peaks remain snow-covered throughout the year.  The mountains are divided into many parallel sub-ranges (up to 10, or 250 km wide), and have the same age and orogenesis as the Alps. Iran's main oilfields lie in the western central foothills of the Zagros mountain range. The highest point of the range is Zard Kuh (4548 metres). The southern ranges of the Fars Province have only somewhat lower summits of up to 4000 m.  The coastline of the Persian Gulf in the south, unlike the northern shores, is rocky and mountainous in some areas and sandy and swampy in others. The only flat area in Iran, beside its central part, is the southern province of Khuzestan (next to Iraq) where major oil fields are located. This is the area that Saddam Hussein had hoped to occupy. Believing that the Tehran regime, denied access to a major part of its oil revenue, would collapse or sue for peace. And we know how that turned out (8 years of bloody war)
Dr. Abbas Bakhtiar