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I spent 10 weeks traveling solo in Iran, and found it to be the safest country out of 70+ that I have traveled in. I found Iranians to be very gracious as a whole, curious about my impressions of their country, and very patient and willing to assist despite the language difficulties. I did learn a few words, and if you know French, you will recognize some words (like "merci" for thank you, instead of the more formal "moteshakeram"). Respect in Iran is a two-way street, it starts with you/me. I was mindful of of my own behaviour and dressed appropriately. I wore a headscarf always and bought a beautiful embroidered and beaded 'manteau' when I arrived - like a lightweight, below-the-knee overcoat (I had mine shortened from floor length). October is a great month to go - the weather is cool without being cold - hence the 'manteau' coverall works great.
I was able to explore widely, quite a bit of it off the beaten path - towards the Iraqi and the Azerbaijani borders, to remote sites like Takht-e-Soleiman, as far east as Mashad, and down to the Gulf. I was very interested in the archaeology, history, and architecture.
Shiraz, Isfahan and Yazd were my favorite cities. More than the various sites visited, it was the experiences that made this trip one of the best ones of my decades-long traveling life - so many, many stories...
Enjoy Iran, and don't listen to the nay-sayers; they simply reflect the profound lack of knowledge that the West maintains about a complex and very rich country - in culture, history, and manners.