Complex sentence: Pompeii has been a tourist destination for over 250 years and today, the UNESCO World Heritage Site is one of the most popular tourist attractions of Italy, with approximately 2.5 million visitors every year.
Split into simpler sentences: Pompeii has been a tourist destination for over 250 years. Today it has UNESCO World Heritage Site status and is one of the most popular tourist attractions of Italy, with approximately 2.5 million visitors every year.