After visiting Athens solo, I decided to play it safe. Tour had about 30 people. We were able to spend enough time at the Blue Mosque and Topkapi palace, although its museums were more crowded than any I have ever seen. We had time for lunch and an hour in the Grand Bazaar on our own. It was enough. I would have been totally lost if I had tried to go on my own so I am satisfied with the excursion.