The Vatican is home to priceless art. The Renaissance was very much alive in Florence, Italy; however artists were commissioned by the clergy and even the pope himself to make masterpieces for the Church. Architects as well like Bernini contributed so much to the rich culture and design of the Vatican.
Vatican City is a city state that came into existence in 1929. It is therefore to be clearly distinguished from the Holy See, which already was in existence for many centuries before that date.
Most visits to the Vatican City are trouble-free but you should be aware of the global risk of indiscriminate international terrorist attacks, which could be against civilian targets, including places frequented by foreigners.