Yes, there is. To visit the Vatican, some rules regarding your clothing should be followed, shoulders and legs should be closed, shorts and t-shirts are inadmissible.

We must be prepared that tourists who visit the sights of the Holy See can not bring their equipment.

In the Vatican museums there are more than 3,000 rooms, and only a few are open for tourists, and the most "fluent" excursion is designed for 3 hours.

You mean the Vatican Museum? There are no special rules, classical clothes. You need a passport with you.