Diferencia entre la Unión Europea y el continente europeo

 The difference is about which group of countries you are comparing with:

• 🇪🇺 “España es el segundo país más extenso de la UE”
  → means Spain is the 2nd largest country in the European Union (after France).
• 🌍 “España es el cuarto país más grande del continente”
  → means Spain is the 4th largest country in the whole European continent, where bigger countries outside the EU are also included (like Russia, Ukraine, etc.).