This is a warning to anyone intending to do the dome climb in St Peter's. There is no warning about the difficulty of this climb. For young fit people it probably isn't a problem but if you are over 60 or have any breathing difficulties then beware. There is an elevator which costs an extra 2 Euros and it does take you part way up but it still leaves you some 326 steps and some inclines to negotiate. It is a one-way system so if you run into problems you have no choice but to continue (heaven knows what happens if anyone has a heart attack). A number of the passage ways are very narrow with no passing places. However, on a clear day, the view is worth it.