My husband and I climbed the Leaning Tower 2 years ago and the Acropolis last May. We are in our 60s. For us, the Acropolis was an easier climb in terms of the steps and you can rest along the way. There are several "flights of stairs" with sloping pathways between. In climbing the Tower I also had to stop and rest along the way. I was concerned about the Acropolis climb, but the climb itself was easier than I anticipated. What can make the Acropolis climb difficult is that you are outdoors in the sun as opposed to inside a tower sheltered from the sun and depending on the time of year, that can be a big factor. There is also no shade within the Acropolis itself, so have water, sunscreen and hats. Have shoes with good traction as the marble can be slippery. Depending on time of year and time of day you go, the Acropolis may be much more crowded than the Leaning Tower as there is a limit to the number of people at each time slot at the Tower. Having said all this, we found the Acropolis to be awe inspiring.