The authorities are still sensitive around the former US Embassy, stormed in 1979. Take a discreet stroll or direct a taxi to drive by what is now labelled the "US Espionage Den" to see the Iranian students' warning daubed on walls: "We will make America face a severe defeat."
Nearby is the Howeyzeh Hotel, which is among the few remaining good- value hotels in the city, since the government introduced a two-tier, dollar-oriented system of charging for foreigners. The hotel costs foreigners $51 a night (much more than for Iranians) but is worth most of its four stars and is a good place to pass quiet nights talking with the friendly staff, who wistfully recall visits to England "before the revolution".
In the heart of Tehran lies the bazaar, conjuring up visions of the tales of Ali Baba and giving you the sense of being at the city's core. Crooked alleyways lead to shops selling a dazzling array of gold-, silver- and ironwork; paths criss-cross, tea houses are numerous and snug; all is mixed with a smell of incense, sweat and butter oil from brass lamps.
If this intensely Middle Eastern experience creates the need to return to the surface for air, head for the northern suburbs.
Traditional accounts of visits to Tehran include tales of illicit alcohol consumption in the far-flung, better-off suburbs. Unfortunately, I must report that the closest I came to alcohol was the Howeyzeh Hotel, where you can buy cans of something revolting called "malt".
But northern Tehran is the place to see a defiantly colourful interpretation of the Islamic dress code. Most women in Tehran wear the chador, the all-enveloping black cloak. But in the shopping arcades of Vali-e-Asr they wear multicoloured scarves and loose-fitting long coats, and their hair, sometimes dyed, hangs visibly over their eyes. They wear conspicuous ponytails, and some sport baseball caps and jeans underneath their cloaks. Even in Tehran, the times are a-changing.