Well, it depends from the time when they can take their vacation. And maybe they have not other possibility to visit these places in an other period. But it's suicide.
I remember, we had to accompany my mother-in-law in Rome in August. It was terribly hot but we decided to rest there for one day and to visit Vatican. I had shorts and a vest top on and did not know it's forbidden to enter the S. Peter's basilica if not completely covered. But I do not stand hot and felt really bad that day. I had giddiness and very law blood pressure. But I wanted to visit basilica so much! Who knows, when I'll have this possibility next time, I thought... In fact, I was not there more.
«castel Sant'Angelo» на Яндекс.Фотках
(If you have to visit basilica, you have to cross this bridge and turn left, as I did. The basilica is about 500 meters from here)
So, as said, I went to the basilica alown: my husband remained to wait near the car because we did not know the city and did not know where to park it, the car, for a moment. No, if you think to visit a big city, it's better to take pubblic transport. You save not only money but many troubles too.
I felt too bad near one of the shops not far from basilica and fall down on it's stairs. The girls in the shop have seen me and gave me water with sugar. It happens very often here, they said. Imagine, they had that water just ready in the shop for those mad like me. I thought about those completely covered persons intended to visit the basilica and about Swiss guards weared with lounge suits. My husband laughs till today when we remember how those bad guards did not allow me to enter in basilica but I just told you that story.
From that time I think twice if I have to visit something in hot summer months. It's better to choose an other direction for the vacation, I think.