With so many great reasons to visit Rome, it's a task in itself to narrow down the must-see attractions. With more than 900 churches alone - that's more than two church visits every day for a year - it's unlikely that you will fit everything into one visit. So, don't try and rush around the city to see every ruin or piazza - save it for your next holiday to Rome!
Ah, Paris! You're oh so beautiful, so romantic, and also, somewhat expensive. The chic boutique hotels, the mouth-watering steak frites, un vin rouge along the Boulevard Saint-Michel - just staying, eating and drinking in the French capital can be a costly experience before you even add on the 'must-see' sights of the city.
Readers who could accept the wildest flights of fancy in a novel - heroes racing against time to avert international disaster and the like - would howl with fury if a character, say, boarded a Northern Line tube train at Green Park or fondly recalled the general election of 1998. Which is why research is as important for my Sam Bourne alter ego as it is in my Jonathan Freedland journalist day job.