The 89,600-square-meter Naghsh-e Jahan Square in Isfahan is one of the biggest squares in the world [Photo by Tan Yingzi/China Daily]

Kashan is also famous for the Fin Garden, completed in 1590, the oldest extant garden in Iran. In 2011 UNESCO put it on the World Heritage List, with eight other gardens in the country.

The heat in Kashan can be searing. From May to October the maximum temperature is generally in the 30s and often in the 40s, and on a hot afternoon nothing matches wandering under cypress trees and by pools and fountains, taking time to admire the watering system that the ancient Persians installed.

When we reluctantly left Kashan it was for Yazd, 390 kilometers by road to the southeast, a city with more than 5,000 years of history and a center of the Zoroastrian religion, one of whose tenets, apparently, is: "Good thoughts, good words and good deeds."

Such things may be difficult to sum up in a place surrounded by desert, where the heat is a sun for giving as that of Kashan, and which is the country's driest city. Particularly impressive here were what are called windcatchers－towers on old buildings whose job is to harness the elements to counteract that unbearable heat.