Portugal's spine is covered by trains and the only place a car is genuinely needed is the Alentejo, which makes multi-day tours largely unnecessary.
Barcelona's food problem is not finding good restaurants but eating at the hours Catalans actually eat, which is later than visitors expect.
Bangkok punishes a walking itinerary planned without regard to the hour, and the good routes are all morning or evening ones.
Japan is the easiest country in Asia to travel independently, which makes packaged tours a solution to a problem most visitors do not have.
Versailles is a train ride and Giverny is not, which is the whole basis for deciding what to book from Paris.
A handful of trips from Rome genuinely justify an organised tour, and they are the ones the trains do not reach.
Guiding earns its price in three specific situations, and none of them is a city centre you could walk with a map.
Reykjavik is small enough to see in a day, which makes the real question what you do with the other four.
Edinburgh's genuinely guided experiences are underground, and everything above ground can be walked for free.
Cape Town's day trips are genuinely better guided, and one category of tour raises questions worth thinking about before booking.
Almost every Cancún excursion can be done independently on a shared van for a fifth of the price, with two genuine exceptions.
Dubai's tour industry sells experiences the metro reaches for a few dirhams, with one genuine exception out in the desert.