These highly commercialised caves were discovered 40 years ago by a local shepherd out looking for a lost goat. They rise to a maximum internal height of 40m (131ft) and have a deep river flowing through the middle. Most Iranians are very proud of Ali Sadr.

One of Iran's Unesco World Heritage sites, Choqa Zanbil's magnificent brick ziggurat is the best surviving example of Elamite architecture anywhere in the world. Even if you're not a fan of ancient ruins, the great bulk and splendid semi-desert isolation of Choqa Zanbil will impress.

The ziggurat originally had five concentric storeys but only three remain, reaching a total height of some 25m (82ft). It's hard to believe that such an imposing landmark was lost to the world for more than 2500 years; it was accidentally spotted in 1935 during an oil company's aerial survey.

Of all the traditional and unspoiled mountain villages in the Caspian Province of Gilan, Masulé (Masuleh) is the most breathtakingly beautiful. It's a cool 1050m (3444ft) above sea level and, formed by several irregular levels of terraced cream houses, appears to have grown out of its surroundings.

There are few facilities here, but Masuleh's inspired setting makes it worth the effort to get here. Masuleh is 56km (35mi) from Rasht, which is six hours north-west by bus from Tehran. From Rasht, take a succession of shared taxis or charter your own.

The astonishing Mil-e Gonbad Tower is so remarkably well preserved that one can scarcely believe it's almost 1000 years old. Soaring 55m (180ft) tall, it has the cross-section of a 10-pointed star, and looks like a buttressed brick spaceship. There's nothing inside except some remarkable echoes.

This spectacular tomb tower is a stunning memorial to the remarkable Qabus ebn-e Vashmgi (of which 'Kavus' is a corruption), a prince, poet, scholar, general and patron of the arts. He ruled the surrounding region at the turn of the 11th century and decided to build a monument to last forever. The tower was completed in 1006, six years before Qabus was slain by an assassin.