Vatican City stands as the world's smallest independent state, a unique urban and landlocked enclave nestled within Rome, Italy. Spanning just 49 hectares (120 acres), its sovereignty extends beyond its main borders to include thirteen extraterritorial buildings in Rome and Castel Gandolfo, such as the Pope's summer residence. This remarkably self-sufficient microstate, built on the ancient Vatican Hill, features a highly optimized urban landscape. Its limited territory ingeniously accommodates diverse infrastructure including a rail line, heliport, post office, military barracks, and the extensive Vatican Gardens, with St. Peter's Basilica being its tallest structure at 138 meters. Sharing Rome's temperate climate, the Vatican famously attempted to become the world's first carbon-neutral state in 2007 via a donated Hungarian forest, though the carbon offsets ultimately did not materialize.