Most "smallest country" lists get the order wrong. Here's the actual top 10 by land area.
1. Vatican City — 0.49 km² The world's smallest country sits inside Rome and is home to about 800 people. The Pope is the head of state.
2. Monaco — 2 km² A French Riviera city-state famous for its casino, royal family, and tax policies. Population density is the world's highest.
3. Nauru — 21 km² A Pacific island that briefly became the world's richest country per capita in the 1970s thanks to phosphate mining — and one of the poorest after the deposits ran out.
4. Tuvalu — 26 km² Nine atolls in the South Pacific. Earns significant revenue from its .tv internet domain.
5. San Marino — 61 km² The world's oldest republic, founded in 301 AD. Completely surrounded by Italy.
6. Liechtenstein — 160 km² A Germanic-speaking principality between Switzerland and Austria. One of only two doubly landlocked countries (the other is Uzbekistan).
7. Marshall Islands — 181 km² A Pacific nation of 1,200+ islands and atolls.
8. Saint Kitts and Nevis — 261 km² The smallest sovereign state in the Western Hemisphere. Famous citizenship-by-investment program.
9. Maldives — 298 km² Famous for resorts, and the lowest-lying country in the world. Climate change is an existential threat.
10. Malta — 316 km² A Mediterranean archipelago with one of the densest histories per square kilometer anywhere.
Bonus: People often mistakenly include the Order of Malta or Sealand — neither is a UN-recognized country.