The smallest country by population is Vatican City, an independent city-state enclaved within Rome, Italy. It has a population of around 800 residents, making it the least populous sovereign state in the world. Vatican City serves as the spiritual and administrative center of the Roman Catholic Church, housing the Pope and significant religious sites such as St. Peter's Basilica and the Sistine Chapel. Despite its small size and population, Vatican City holds substantial global influence and plays a vital role in diplomacy and religious affairs.