The Lateran Treaty of 1929 declared Vatican City an independent state, giving the Holy See sovereignty over a small territory within Rome that covers just over 100 acres. This square mile patch of land was not legally part of Italy and remains the world's smallest internationally recognized independent state.

2. Lateran Treaty 1929 – Vatican City was declared independent. A square mile in Rome that was not legally bound to Italy. (It is the smallest country in the world)