Hugging the lower slopes of the magnificent, snowcapped Alborz Mountains, Tehran is Iran’s most secular and liberal city. Spend time here – as you should – and you'll soon realise that the city is so much more than a chaotic jumble of concrete and crazy traffic blanketed by a miasma of air pollution. This is the nation's dynamic beating heart and the place to get a handle on modern Iran and what its future will likely be.